Acanthosis nigricans is a skin condition characterized by areas of dark, velvety discoloration in body folds and creases. The affected skin can become thickened. Most often, acanthosis nigricans affects your armpits, groin and neck. The sk...

Seborrheic Keratosis is a skin disorder usually characterized by discolored lesions that appear to be "stuck on" the skin surface. Warts may appear and skin is often oily or greasy. These skin lesions are sometimes mistaken for cancerous growths a...

Acne is a skin condition that occurs when your hair follicles become plugged with oil and dead skin cells. It often causes whiteheads, blackheads or pimples, and usually appears on the face, forehead, chest, upper back and shoulders. Acne is most ...

Acne (acne vulgaris, common acne) is a disease of the hair follicles of the face, chest, and back that affects almost all teenagers during puberty -- the only exception being members of a few primitive Neolithic tribes living in isolatio...

Classical lissencephaly, also known as lissencephaly type I, is a brain malformation that may occur as an isolated abnormality (isolated lissencephaly sequence [ILS]) or in association with certain underlying syndromes (e.g., Miller-Dieker syndrom...

Osteopetrosis may be inherited as either a dominant or recessive trait and is marked by increased bone density, brittle bones, and, in some cases, skeletal abnormalities. Although symptoms may not initially be apparent in people with mild forms of...

The term albinism typically refers to oculocutaneous (ok-u-low-ku-TAY-nee-us) albinism (OCA) — a group of inherited disorders where there is little or no production of the pigment melanin. The type and amount of melanin your body produces de...

MCT8-specific thyroid hormone cell transporter deficiency (THCT deficiency) is an inherited disorder that is characterized by severe mental retardation, an impaired ability to speak, diminished muscle tone (hypotonia), and/or movement abnormalitie...

MCT8-specific thyroid hormone cell transporter deficiency (THCT deficiency) is an inherited disorder that is characterized by severe mental retardation, an impaired ability to speak, diminished muscle tone (hypotonia), and/or movement abnormalitie...

Tangier Disease is an inherited blood disorder involving decreased concentrations of fat compounds in the blood called high-density lipoproteins (sometimes called "good cholesterol"). Large amounts of these compounds may accumulate in certain orga...

Amblyopia, also known as lazy eye, is a vision development disorder in which an eye fails to achieve normal visual acuity, even with prescription eyeglasses or contact lenses. It is the most common cause of vision problems in children. Amblyopia i...

Amelogenesis Imperfecta is a rare genetic disorder that affects the development of tooth enamel. People with this condition have abnormal enamel formation, which can result in teeth that are discolored, pitted, or prone to rapid wear and breakage....

Angular cheilitis, also known as perleche, is a common inflammatory condition that affects the corners of the mouth. It is characterized by redness, cracking, and sometimes painful sores at the corners of the lips. The condition can be caused by a...

Arthritis is the swelling and tenderness of one or more joints. The main symptoms of arthritis are joint pain and stiffness, which typically worsen with age. The most common types of arthritis are osteoarthritis and rheumatoid arthritis. O...

Arthritis is the swelling and tenderness of one or more joints. The main symptoms of arthritis are joint pain and stiffness, which typically worsen with age. The most common types of arthritis are osteoarthritis and rheumatoid arthritis. O...

Infectious arthritis is an inflammation of one or more joints that occurs as a result of infection by bacteria, viruses or, less frequently, fungi or parasites. The symptoms of Infectious arthritis depend upon which agent has caused the infection ...

OverviewArteriosclerosis occurs when the blood vessels that carry oxygen and nutrients from your heart to the rest of your body (arteries) become thick and stiff — sometimes restricting blood flow to your organs and tissues. Healthy art...

Arteriosclerosis occurs when the blood vessels that carry oxygen and nutrients from your heart to the rest of your body (arteries) become thick and stiff — sometimes restricting blood flow to your organs and tissues. Healthy arteries are fle...

Athlete's foot, also known as tinea pedis, is a common fungal infection that affects the skin on the feet. It is caused by various types of fungi, most commonly Trichophyton rubrum. Athlete's foot is highly contagious and can be spread through dir...

Atopic dermatitis facts Atopic dermatitis is a type of eczema. The disease may be inherited and genetically determined. The patient's skin may be "super sensitive" to many irritants. Dry, scaly patches ...

Atrial fibrillation (A-fib) is an irregular and often very rapid heart rhythm (a...

Atrial fibrillation (A-fib) is an irregular and often very rapid heart rhythm (arrhythmia) that can lead to blood clots in the heart. A-fib increases the risk of stroke, heart failure and other he...

Romano-Ward syndrome is an inherited heart (cardiac) disorder characterized by abnormalities affecting the electrical system of the heart. The severity of Romano-Ward syndrome varies greatly from case to case. Some individuals may have no apparent...

Bacterial keratitis is an infection of the cornea, the clear outer layer of the eye, caused by bacteria. Symptoms of bacterial keratitis include redness, pain, light sensitivity, blurred vision, and discharge from the eye. Treatment typically invo...

A balance disorder is a condition that makes you feel unsteady or dizzy, as if you are moving, spinning, or floating, even though you are standing still or lying down. Balance disorders can be caused by certain health conditions, medications, or a...

Batten disease, a rare genetic disorder, belongs to a group of progressive degenerative neurometabolic disorders known as the neuronal ceroid lipofuscinoses. These disorders share certain similar symptoms and are distinguished in part by the age a...

Batten disease, a rare genetic disorder, belongs to a group of progressive degenerative neurometabolic disorders known as the neuronal ceroid lipofuscinoses. These disorders share certain similar symptoms and are distinguished in part by the age a...

Bile duct cancer, also called cholangiocarcinoma, is when unusual cells grow out of control inside your bile ducts. Those are thin tubes about 4 to 5 inches long that move a fluid called bile from your liver to your gallbladder and small intestine...

Bile duct cancer, also called cholangiocarcinoma, is when unusual cells grow out of control inside your bile ducts. Those are thin tubes about 4 to 5 inches long that move a fluid called bile from your liver to your gallbladder and small intestine...

Black Eye is a mobile photography app that allows users to take and edit photos with a variety of filters, effects, and tools. It also includes features such as face recognition, portrait mode, and a variety of other editing tools....

Hairy tongue is an uncommon, benign condition that is also known as black hairy tongue or lingua nigra. It is characterized by abnormal elongation and blackish or dark brownish discoloration or "staining" of the thread-like elevations (filiform pa...

Blepharitis is an inflammation of the eyelids. It is a common condition that can cause redness, itching, burning, and a gritty sensation in the eyes. It can also cause the eyelids to become swollen, crusty, and flaky. Blepharitis is usually caused...

Blue rubber bleb nevus syndrome (BRBNS) is a rare blood vessel (vascular) disorder that affects the skin and internal organs of the body. Multiple distinctive skin lesions are usually characteristic of this disorder and are often present at birth ...

Boil  A boil is a painful, pus-filled bump under your skin — the result of a bacterial infection of one or more hair follicles. Carbuncle  A carbuncle is a cluster of boils — painful, pus-filled bumps ...

The botulism neurotoxin is one of the most potent, lethal substances known. Botulism is a disease caused by this neurotoxin (specifically A, B, E, or F type neurotoxin). The neurotoxin is produced by bacteria called Clostr...

Bowen disease is a rare skin disorder. Affected individuals develop a slow-growing, reddish scaly patch or plaque on the skin. Sun exposed areas of the skin are most often affected. Bowen disease only affects the outermost layer of the skin (epide...

Brain aneurysm  An aneurysm is a ballooning at a weak spot in an artery wall. An aneurysm's walls can be thin enough to rupture. The illustration shows an individual with an unruptured aneurysm. The inset shows what happens when the a...

A brain tumor is a mass or growth of abnormal cells in your brain. Many different types of brain tumors exist. Some brain tumors are noncancerous (benign), and some brain tumors are cancerous (malignant). Brain tumors can begin in your bra...

A brain tumor is a mass or growth of abnormal cells in your brain. Many different types of brain tumors exist. Some brain tumors are noncancerous (benign), and some brain tumors are cancerous (malignant). Brain tumors can begin in your bra...

A brain tumor is a mass or growth of abnormal cells in your brain. Many different types of brain tumors exist. Some brain tumors are noncancerous (benign), and some brain tumors are cancerous (malignant). Brain tumors can begin in your bra...

Breast cancer is the most common cancer in pregnant women and tends to affect women in their mid-30s. Although only about 1 in every 1,000 pregnant women get breast cancer, the disease can be devastating to both the mother and her child -- so it i...

Younger women generally do not consider themselves to be at risk for breast cancer. Only 5 percent of all breast cancer cases occur in women under 40 years old. However, breast cancer can strike at any age, and all women should be aware of their p...

Facing a breast cancer diagnosis can be overwhelming. Your stress levels may skyrocket. You may worry about finances. And you may be asking yourself difficult questions, such as whether to write a living will. Education and supportive care can hel...

Facing a breast cancer diagnosis can be overwhelming. Your stress levels may skyrocket. You may worry about finances. And you may be asking yourself difficult questions, such as whether to write a living will. Education and supportive care can hel...

Bronchitis is an infection that causes irritation and inflammation in the lungs' major airways (bronchi). Bronchitis is divided into two types: acute and chronic. Chronic bronchitis is a long-term condition that can reoccur. Long-term stress, such...

Bronchitis is an infection that affects the lungs' major airways (bronchi), causing irritation and inflammation. Bronchitis can be classified into two types: acute and long-term. Chronic bronchitis is a long-term problem that can come back. It is usu...

Bulimia nervosa facts Bulimia is an eating disorder that is characterized by episodes of binging and purging the food and or associated calories. Bulimia is a significant public-health problem, both because of the physical...

Bullous pemphigoid is an uncommon skin disease characterized by tense blisters on the surface of the skin. Occasionally, the inner lining tissue of the mouth, nasal passages, or conjunctivae of the eyes (mucous membrane tissue) can be involved. Th...

Bunions facts Bunions involve boney prominences and repositioning of the joints at the base of the big toes. Bunions most commonly affect the inner foot at the base of the big toe but also can affect the outside of the foo...

Familial articular chondrocalcinosis is a rare inherited metabolic disorder characterized by deposits of calcium pyrophosphate dihydrate crystals (CPPD) in one or more joint cartilages resulting in eventual damage to the joints. Symptoms may devel...

Gordon syndrome is an extremely rare disorder that belongs to a group of genetic disorders known as the distal arthrogryposes. These disorders typically involve stiffness and impaired mobility of certain joints of the lower arms and legs (distal e...

Canker sores, also known as aphthous ulcers, are small, painful sores that develop on the inside of the mouth, on the gums, or on the tongue. They are usually round or oval in shape and have a white or yellow center with a red border. Canker sores...

Pinta is a rare infectious tropical disease affecting the skin that is caused by the bacterium Treponema carateum, which is transmitted by direct, nonsexual contact. Pinta progresses through three distinct stages, which are characterized by variou...

Cataracts are a clouding of the lens in the eye that affects vision. Most cataracts are related to aging. Symptoms may include blurry vision, poor night vision, sensitivity to light and glare, faded colors, halos around lights, and double vision i...

  Cellulitis is a spreading bacterial infection of the skin and tissues beneath the skin. Staphylococcus and Streptococcus are the types of bacteria that are usually responsible for cellulitis, although many types of ...

Cellulitis is a bacterial infection of the skin and underlying tissue. It is usually caused by bacteria such as Staphylococcus aureus or Streptococcus. Symptoms of cellulitis include redness, swelling, warmth, and pain in the affected area. If lef...

Central serous chorioretinopathy (CSC) is a disorder of the eye in which fluid accumulates beneath the retina, causing it to detach from the back of the eye. This can lead to blurred vision, distortion of vision, and blind spots. CSC is usually ca...

Chanarin Dorfman syndrome is a rare hereditary disorder of fat (lipid) metabolism. It is characterized by scaly skin (ichthyosis), degeneration of the muscles (myopathy), and abnormal white blood cells with small spaces (vacuoles) filled with fat ...

Chediak-Higashi syndrome (CHS) is a rare, inherited, complex, immune disorder of childhood (usually) characterized by abnormally pale skin and eyes (oculocutaneous albinism). Because the patient's white blood cells (leukocytes) are profoundly affe...

Chediak-Higashi syndrome (CHS) is a rare, inherited, complex, immune disorder of childhood (usually) characterized by abnormally pale skin and eyes (oculocutaneous albinism). Because the patient's white blood cells (leukocytes) are profoundly affe...

Cheek biting, also known as cheek chewing or morsicatio buccarum, is a habit in which a person repeatedly bites or chews on the inside of their cheek. This behavior can be caused by stress, anxiety, or nervousness, and can lead to irritation, pain...

Chickenpox (varicella) is a viral infection that causes an itchy rash with small, fluid-filled blisters. Chickenpox is highly contagious to people who haven't had the disease or been vaccinated against it. Before routine chickenpox vaccination, vi...

Chilblains (CHILL-blayns) are the painful inflammation of small blood vessels in your skin that occur in response to repeated exposure to cold but not freezing air. Also known as pernio, chilblains can cause itching, red patches, swelling and blis...

CHILD syndrome (an acronym for congenital hemidysplasia with ichthyosiform erythroderma and limb defects) is an inherited disorder, affecting primarily women, that is characterized by ichthyosis-like skin abnormalities and limb defects on one side...

CHILD syndrome (an acronym for congenital hemidysplasia with ichthyosiform erythroderma and limb defects) is an inherited disorder, affecting primarily women, that is characterized by ichthyosis-like skin abnormalities and limb defects on one side...

Giant axonal neuropathy is a rare neuropathy that severely affects the peripheral as well as the central nervous system. The first symptoms appear in early childhood. This disorder is characterized by abnormalities in the peripheral and central ne...

Haim-Munk syndrome is a rare genetic disorder characterized by the development of red, scaly thickened patches of skin on the palms of the hands and soles of the feet (palmoplantar hyperkeratosis), frequent pus-producing (pyogenic) skin infections...

Coffin-Lowry syndrome is a rare genetic disorder characterized by mental retardation; abnormalities of the head and facial (craniofacial) area; large, soft hands with short, thin (tapered) fingers; short stature; and/or various skeletal abnormalit...

Coffin-Lowry syndrome is a rare genetic disorder characterized by mental retardation; abnormalities of the head and facial (craniofacial) area; large, soft hands with short, thin (tapered) fingers; short stature; and/or various skeletal abnormalit...

Cold antibody hemolytic anemia (CAHA) is a rare autoimmune disorder characterized by the premature destruction of red blood cells (rbcs) by the body's natural defenses against invading organisms (antibodies). Normally, the red blood cells have a l...

Ulcerative colitis (UL-sur-uh-tiv koe-LIE-tis) is an inflammatory bowel disease ...

Ulcerative colitis (UL-sur-uh-tiv koe-LIE-tis) is an inflammatory bowel disease (IBD) that causes inflammation and ulcers (sores) in your digestive tract. Ulcerative colitis affects the innermost lining of your large intestine (colon) and rectum. ...

Conjunctivitis, commonly known as pink eye, is an inflammation of the conjunctiva, the thin, transparent membrane that lines the inner surface of the eyelid and covers the white part of the eye. It is usually caused by a bacterial or viral infecti...

Mixed connective tissue disease facts Connective tissues are the framework of the cells of the body. Mixed connective tissue disease is an "overlap" combination of connective tissue diseases. Diagnosis of mixed c...

Contact dermatitis facts Contact dermatitis is a rash that occurs at the site of exposure to a substance capable of producing an allegic or irritant skin response. Contact dermatitis can be caused by noxious, irritating su...

Contact lens-related eye infections are infections of the eye caused by the improper use of contact lenses. These infections can range from mild to severe and can cause a variety of symptoms, including redness, itching, burning, and blurred vision...

Corneal abrasion is a condition in which the outer layer of the cornea (the clear, dome-shaped surface that covers the front of the eye) is scratched or scraped. It is a common eye injury that can cause pain, redness, tearing, and light sensitivit...

Corneal laceration is a tear or cut in the cornea, the clear, dome-shaped surface that covers the front of the eye. It is usually caused by a sharp object, such as a fingernail, a piece of metal, or a tree branch. Corneal lacerations can cause pai...

A corneal ulcer is an open sore on the cornea, the clear dome-shaped surface that covers the front of the eye. It is usually caused by an infection, such as bacterial, viral, or fungal, or by an injury to the eye. Symptoms of a corneal ulcer inclu...

Cradle cap causes crusty or oily scaly patches on a baby's scalp. The condition isn't painful or itchy. But it can cause thick white or yellow scales that aren't easy to remove. Cradle cap usually clears up on its own in a few months. Home...

Creutzfeldt-Jakob disease (CJD) is a rare, degenerative, invariably fatal brain disorder. It affects about one person in every one million people per year worldwide; in the United States there are about 200 cases per year. CJD usually appears in l...

Crohn's disease facts Crohn's disease is a chronic inflammatory disease of the intestines. The cause of Crohn's disease is unknown. Crohn's disease can cause ulcers in the small intestine, colon, or both. ...

Gianotti-Crosti Syndrome is a rare skin disease affecting children between the ages of nine months and nine years. Major symptoms may include blisters on the skin of the legs, buttocks and arms. The disorder is usually preceded by a viral infectio...

Mixed cryoglobulinemia is a rare disorder characterized by the presence of cryoglobulins in the blood. Cryoglobulins are abnormal proteins that thicken and clump together at cold temperatures, usually below 98.6 degrees Fahrenheit (the average hum...

Fraser syndrome is a rare genetic disorder characterized by partial webbing of the fingers and/or toes (partial syndactyly), kidney (renal) abnormalities, genital malformations, and/or, in some cases, complete fusion of the eyelids (cryptophthalmo...

Cyst facts Cysts are closed sac-like or capsule structures that may be filled with semisolid material, gaseous material, or liquid. There are several causes of cysts, including genetic, infectious, and other causes that resu...

Peeling skin syndrome is a rare inherited skin disorder characterized by painless, continual, spontaneous skin peeling (exfoliation). Other findings may include blistering and/or reddening of the skin (erythema) and itching (pruritus). Peeling ski...

Degos disease is an extremely rare disorder in which small and medium sized arteries become blocked (occlusive arteriopathy), restricting the flow of blood to affected areas. Degos disease usually causes characteristic skin lesions that may last f...

Degos disease is an extremely rare disorder in which small and medium sized arteries become blocked (occlusive arteriopathy), restricting the flow of blood to affected areas. Degos disease usually causes characteristic skin lesions that may last f...

Dentinogenesis Imperfecta is a genetic disorder that affects the development of tooth dentin, which is the hard tissue that makes up the majority of a tooth. This condition results in teeth that are discolored, weak, and prone to breaking or weari...

Determining hearing loss in children facts Children can be tested for hearing loss at any age. There are several risk factors associated with hearing loss, including ear infections, prematurity, diseases, and syndromes....

Diabetes and foot problems facts Two main conditions, peripheral artery disease (PAD) and peripheral neuropathy, are responsible for the increased risk of foot problems in people with diabetes. People with diabetes have an...

Type 2 diabetes is an impairment in the way the body regulates and uses sugar (g...

Diabetic eye disease is a group of eye problems that can occur in people with diabetes. These eye problems can include diabetic retinopathy, cataracts, and glaucoma. Diabetic retinopathy is the most common form of diabetic eye disease and is cause...

Diabetic retinopathy is a complication of diabetes that affects the eyes. It occurs when high blood sugar levels damage the blood vessels in the retina, the light-sensitive tissue at the back of the eye. This can lead to vision loss or blindness. ...

Hereditary multiple osteochondromas (HMO) is a rare genetic disorder characterized by multiple benign (noncancerous) bone tumors that are covered by cartilage (osteochondromas), often on the growing end (metaphysis) of the long bones of the legs, ...

Diastrophic dysplasia, which is also known as disastrophic dwarfism, is a rare disorder that is present at birth (congenital). The range and severity of associated symptoms and physical findings may vary greatly from case to case. However, the dis...

Dislocated ankle facts An isolated dislocated ankle is a rare injury. Usually, there is an associated fracture of the bones that make up the ankle. The ankle dislocates as a result of a fall, motor-vehicle crash, or sporti...

CHILD syndrome (an acronym for congenital hemidysplasia with ichthyosiform erythroderma and limb defects) is an inherited disorder, affecting primarily women, that is characterized by ichthyosis-like skin abnormalities and limb defects on one side...

Chanarin Dorfman syndrome is a rare hereditary disorder of fat (lipid) metabolism. It is characterized by scaly skin (ichthyosis), degeneration of the muscles (myopathy), and abnormal white blood cells with small spaces (vacuoles) filled with fat ...

Alexander disease is named after the physician who first described the condition in 1949 (WS Alexander). It is an extremely rare, usually progressive and fatal, neurological disorder. Initially it was detected most often during infancy or early ch...

Dysthymia, now referred to as persistent depressive disorder, is a form of depression that lasts more than two years at a time in adults and more than one year at a time in children and adolescents. Dysthymia can afflict 3%-6% of th...

Ehlers-Danlos syndrome (EDS) is a group of hereditary connective tissue disorders characterized by defects of the major structural protein in the body (collagen). Collagen, a tough, fibrous protein, plays an essential role in holding together, str...

Eales Disease is a rare disorder of sight that appears as an inflammation and white haze around the outercoat of the veins in the retina. The disorder is most prevalent among young males and normally affects both eyes. Usually, vision is suddenly ...

Rapp-Hodgkin syndrome, an extremely rare inherited multisystem disorder that is apparent at birth (congenital) or during infancy, belongs to a group of diseases known as ectodermal dysplasias. Ectodermal dysplasias typically affect the skin, teeth...

Johanson-Blizzard syndrome (JBS) is an extremely rare genetic disorder that affects multiple organ systems of the body. Many symptoms are present at birth (congenital) or early childhood. The spectrum of potential features and physical findings as...

Eczema facts Eczema is not a single disease but a reaction pattern of the skin produced by a number conditions. Atopic dermatitis, a common causes of eczema, is more prevalent in those with asthma and hay fever. ...

Ehlers-Danlos syndrome (EDS) is a group of hereditary connective tissue disorders characterized by defects of the major structural protein in the body (collagen). Collagen, a tough, fibrous protein, plays an essential role in holding together, str...

General DiscussionEisenmenger syndrome is a rare progressive heart condition that develops in some individuals with structural malformations of the heart that are present from birth (congenital heart defects). The disorder is characterize...

Elbow pain facts The elbow joint is the area of union of three long bones. Tendinitis can affect the inner or outer elbow. Treatment of tendinitis includes ice, rest, and medication for inflammation. Ba...

Pinta is a rare infectious tropical disease affecting the skin that is caused by the bacterium Treponema carateum, which is transmitted by direct, nonsexual contact. Pinta progresses through three distinct stages, which are characterized by variou...

Enamel hypoplasia is a developmental defect of the teeth in which the enamel does not form properly, resulting in thin or missing enamel on the teeth. This can lead to increased sensitivity, discoloration, and an increased risk of tooth decay. Ena...

Atrioventricular septal defect (ASVD) is a general term for a group of rare heart defects that are present at birth (congenital). Infants with ASVDs have improperly developed atrial and ventricular septa and adjoining valves. The norma...

Carcinoid syndrome is a disease consisting of a combination of symptoms, physical manifestations, and abnormal laboratory findings. Carcinoid syndrome is seen in individuals who have an underlying carcinoid tumour with spread to the liver. Carcino...

Endophthalmitis is an inflammation of the inner layers of the eye, usually caused by an infection. It can be caused by bacteria, fungi, or viruses, and can lead to vision loss if not treated promptly. Symptoms of endophthalmitis include redness, p...

Epidermolytic ichthyosis (EI) specifically refers to a hereditary skin disorder that is characterized by varying degrees of blistering and subsequent reactive scaling of the skin. The underlying histopathology shows mid-epidermal splitting and hyp...

The largest part of the brain, the cerebrum, is divided into four paired sections -- the frontal, parietal, occipital, and temporal lobes. Each lobe controls a specific group of activities. The temporal lobe, located on either side of the brain ju...

The largest part of the brain, the cerebrum, is divided into four paired sections -- the frontal, parietal, occipital, and temporal lobes. Each lobe controls a specific group of activities. The temporal lobe, located on either side of the brain ju...

Tuberous sclerosis is a rare genetic multisystem disorder that is typically apparent shortly after birth. The disorder may be characterized by episodes of uncontrolled electrical activity in the brain (seizures); mental retardation; distinctive sk...

An eruption cyst is a benign, soft tissue swelling that occurs in the mouth when a tooth is about to erupt through the gum. It appears as a small, fluid-filled blister that is usually purple or blue in color. Eruption cysts are most commonly seen ...

Erythema multiforme (EM) is the name applied to a group of hypersensitivity disorders, affecting mostly children and young adults, and characterized by symmetric red, patchy lesions, primarily on the arms and legs. The cause is unknown, but EM fre...

Until recently the relationship of Stevens-Johnson syndrome to other severe blistering disorders was a matter of some debate. Now a consensus seems to be evolving that describes SJS as a rare disorder involving lesions of the mucous membranes alon...

Erythema nodosum is a type of skin inflammation that is located in a certain portion of the fatty layer of skin. Erythema nodosum (also called EN) results in reddish, painful, tender lumps most commonly located in the front of the legs below the k...

Erythromelalgia is a rare condition that primarily affects the feet and, less commonly, the hands (extremities). It is characterized by intense, burning pain of affected extremities, severe redness (erythema), and increased skin temperature that m...

Polycythemia vera is a rare, chronic disorder involving the overproduction of blood cells in the bone marrow (myeloproliferation). The overproduction of red blood cells is most dramatic, but the production of white blood cells and platelets are al...

Erythrokeratolysis hiemalis is an extremely rare form of ichthyosis that was first described in South Africa but has subsequently been identified in other countries. In such cases, a link to South Africa has been determined. The disorder is charac...

Erythroplakia is a condition characterized by red patches or lesions on the mucous membranes of the mouth, throat, or other areas of the body. These patches are often smooth, velvety, and may bleed easily when touched. Erythroplakia is considered ...

Cryptococcosis is caused by a fungus known as Cryptococcosis neoformans. The infection may be spread to humans through contact with pigeon droppings or unwashed raw fruit. Contact with an infected individual may also spread the infection. Individu...

Hereditary multiple osteochondromas (HMO) is a rare genetic disorder characterized by multiple benign (noncancerous) bone tumors that are covered by cartilage (osteochondromas), often on the growing end (metaphysis) of the long bones of the legs, ...

Eye allergies, also known as allergic conjunctivitis, are a type of allergic reaction that affects the eyes. Symptoms of eye allergies include redness, itching, burning, tearing, and swelling of the eyes. Eye allergies are usually caused by airbor...

Eye lymphoma is a type of cancer that affects the eye. It is a rare form of non-Hodgkin lymphoma, which is a type of cancer that affects the lymphatic system. Eye lymphoma can affect the eye itself, the orbit (the area around the eye), or the eyel...

Fabry disease is caused by the lack of or faulty enzyme needed to metabolize lipids, fat-like substances that include oils, waxes, and fatty acids. The enzyme is known as ceramide trihexosidase, also called alpha-galactosidase-A. A mutation in the...

Peeling skin syndrome is a rare inherited skin disorder characterized by painless, continual, spontaneous skin peeling (exfoliation). Other findings may include blistering and/or reddening of the skin (erythema) and itching (pruritus). Peeling ski...

Familial eosinophilic cellulitis is a rare skin disorder. It is characterized by raised, red, swollen, and warm areas of skin, in a flame-shaped pattern with associated pain. The exact cause of the disease is unknown. However, bites of spiders, be...

You have flatfeet when the arches on the inside of your feet are flattened, allowing the entire soles of your feet to touch the floor when you stand up. A common and usually painless condition, flatfeet can occur when the arches don't deve...

Focal dermal hypoplasia (FDH), also known as Goltz syndrome, is a rare skin disorder that can also affect bone and eye development. If is a type of ectodermal dysplasia, a group of heritable disorders causing the hair, teeth, nails, and glands to ...

Focal dermal hypoplasia (FDH), also known as Goltz syndrome, is a rare skin disorder that can also affect bone and eye development. If is a type of ectodermal dysplasia, a group of heritable disorders causing the hair, teeth, nails, and glands to ...

Formaldehyde is a transitional molecule that participates in a wide range of biological activities. It can be found in a variety of everyday items, including meals. It's also used in medicine to treat a variety of ailments. Formalin is a 40 percen...

Frozen shoulder facts Frozen shoulder is the result of scarring, thickening, and shrinkage of the joint capsule. Any injury to the shoulder can lead to a frozen shoulder. A frozen shoulder is usually diagnosed du...

Fructosuria is a rare but benign inherited metabolic disorder. It is characterized by the excretion of fruit sugar (fructose) in the urine. Normally, no fructose is excreted in the urine. This condition is caused by a deficiency of the enzyme fruc...

Fungal keratitis is an infection of the cornea, the clear outer layer of the eye, caused by a fungus. It is a rare but serious condition that can cause vision loss if not treated promptly. Symptoms of fungal keratitis include redness, pain, blurre...

Gangrene facts Gangrene refers to dead or dying body tissue(s) that occur because of inadequate blood supply. There are two major types of gangrene, wet gangrene and dry gangrene. Dry gangrene can result from con...

Though ulcers often heal on their own, you shouldn't ignore their warning signs. If not properly treated, ulcers can lead to serious health problems, including: Bleeding Perforation (a hole through the wall of the stomach)...

Geographic tongue, also known as benign migratory glossitis, is a harmless condition characterized by irregular patches on the surface of the tongue that resemble a map. These patches can vary in size, shape, and color, and may come and go over ti...

Giant Papillary Conjunctivitis (GPC) is an inflammatory condition of the eye that affects the inner surface of the eyelids. It is caused by an allergic reaction to contact lenses, foreign bodies, or other irritants. Symptoms include itching, redne...

Aniridia, cerebellar ataxia, and mental deficiency, also known as Gillespie syndrome, is an extremely rare inherited disorder that is characterized by the absence, in whole (aniridia) or in part (partial aniridia), of the colored portion (iris) of...

Erythrokeratodermia with ataxia (EKDA) is a hereditary disorder of the skin and nervous system (neurocutaneous syndrome) characterized by groups of hard, red plaques that develop during infancy and childhood. When these skin lesions heal, the diso...

Glaucoma is a disease that is often associated with elevated intraocular pressure, in which damage to the eye (optic) nerve can lead to loss of vision and even blindness. Glaucoma is the leading cause of irreversible blindness in th...

Glaucoma is a group of eye diseases that damage the optic nerve, which carries information from the eye to the brain. It is usually caused by an abnormally high pressure in the eye, which can damage the optic nerve and lead to vision loss. Glaucom...

Glossitis is a condition characterized by inflammation of the tongue. This inflammation can cause the tongue to become swollen, red, and painful. Glossitis can be caused by a variety of factors, including infections, allergies, nutritional deficie...

Gaucher disease is a rare, inherited metabolic disorder in which deficiency of the enzyme glucocerebrosidase results in the accumulation of harmful quantities of certain fats (lipids), specifically the glycolipid glucocerebroside, throughout the b...

Andersen disease belongs to a group of rare genetic disorders of glycogen metabolism, known as glycogen storage diseases. Glycogen is a complex carbohydrate that is converted into the simple sugar glucose for the body's use as energy. Glycogen sto...

Fabry disease is a rare genetic disorder of fat (lipid) metabolism characterized by a deficiency of the enzyme alpha-galactosidase A (previously known as ceramide trihexosidase). The disorder belongs to a group of diseases known as lysosomal stora...

Gout is a type of arthritis that causes inflammation, usually in one joint, that begins suddenly. Gouty arthritis is caused by the deposition of crystals of uric acid in a joint. Gout can cause symptoms and signs such as ...

Gout is a type of arthritis that causes inflammation, usually in one joint, that begins suddenly. Gouty arthritis is caused by the deposition of crystals of uric acid in a joint. Gout can cause symptoms and signs such as ...

Granuloma annulare (gran-u-LOW-muh an-u-LAR-e) is a skin condition that most commonly consists of raised, reddish or skin-colored bumps (lesions) that form ring patterns — usually on your hands and feet. No one knows exactly what cau...

Familial eosinophilic cellulitis is a rare skin disorder. It is characterized by raised, red, swollen, and warm areas of skin, in a flame-shaped pattern with associated pain. The exact cause of the disease is unknown. However, bites of spiders, be...

Grover's disease is a rare, transient skin disorder that consists of small, firm, raised red lesions, most often on the skin of the chest and back. Diagnosis of this disorder becomes apparent under microscopic examination when the loss of the "cem...

A gum boil, also known as a dental abscess, is a painful swelling filled with pus that forms on the gums. It is usually caused by a bacterial infection in the tooth or gums and can be a result of tooth decay, gum disease, or a dental injury. Gum b...

Lichen sclerosus is a chronic skin disorder that most commonly affects post-menopausal women. However, it is sometimes identified among pre-menopausal women, and, even more rarely, among males. When found in males, the disease is known as balaniti...

Congenital central hypoventilation syndrome (CCHS) is a rare disorder of respiratory control with autonomic nervous system dysregulation (ANSD). The autonomic nervous system is the portion of the nervous system that controls or regulates certain i...

Hajdu-Cheney syndrome (HCS) is a rare, heritable disorder of connective tissue; only about 50 cases have been reported in the medical literature. The breakdown of bone (osteolysis), especially the outermost bones of the fingers and toes (acroosteo...

Harlequin ichthyosis is a rare genetic skin disorder. The newborn infant is covered with plates of thick skin that crack and split apart. The thick plates can pull at and distort facial features and can restrict breathing and eating. Harlequin inf...

Hartnup disease is a rare metabolic disorder inherited as an autosomal recessive trait. It involves an inborn error of amino acid metabolism as well as niacin deficiency. Factors that may precipitate acute attacks of this disorder may include poor...

Head lice, also known as pediculosis, are tiny parasitic insects that live on the scalp and feed on human blood. They are common among school-aged children and can easily spread through close personal contact or by sharing personal items such as h...

Introduction to heart transplant The idea of replacing a bad organ with a good one has been documented in ancient mythology. The first real organ transplants were probably skin grafts that may have been done in India as early as the second...

Helicobacter pylori (H. pylori) facts Helicobacter pylori (H. pylori) is a bacterium that causes chronic inflammation in the stomach and is a common cause of ulcers worldwide H. pylori causes chronic inflammation (gastriti...

Hemangioma is a benign (non-cancerous) tumor made up of a cluster of blood vessels. It is most commonly found in infants and young children, and usually appears as a red or purple mark on the skin. Hemangiomas can occur anywhere on the body, but a...

Hemangioma is a noncancerous growth of blood vessels that can occur anywhere in the body. It is most commonly found on the skin or internal organs, such as the liver or lungs. Hemangiomas are usually present at birth or develop shortly after and c...

A hematoma is a collection of blood outside of a blood vessel. Symptoms of hematomas depend upon their location and whether adjacent structures are affected by the inflammation and swelling associated with the bleeding. Tr...

Herpes Keratitis is an infection of the cornea caused by the herpes simplex virus (HSV). It is a common cause of corneal blindness and can cause severe vision loss if left untreated. Symptoms of Herpes Keratitis include redness, pain, light sensit...

Herpes Zoster, commonly known as shingles, is a viral infection caused by the varicella-zoster virus, the same virus that causes chickenpox. It is characterized by a painful rash with blisters that typically appears on one side of the face or body...

Heterochromia is a condition in which a person has two different colored eyes. It can be caused by genetics, injury, or disease....

Hidradenitis suppurativa (HS) is a chronic condition characterized by swollen, painful lesions, occurring in the armpit (axillae), groin, anal, and breast regions. This disease occurs due to obstruction of hair follicles and secondary infection an...

Hidradenitis suppurativa (hi-drad-uh-NIE-tis sup-yoo-ruh-TIE-vuh) is rare, long-term skin condition that features small, painful lumps under the skin. They typically develop where the skin rubs together, such as the armpits, the groin, between the...

HIV/AIDS and the Eye is a term used to describe the effects of HIV/AIDS on the eyes. HIV/AIDS can cause a variety of eye problems, including inflammation of the eye, dry eye, and vision loss. HIV/AIDS can also increase the risk of developing certa...

Papular urticaria, usually called hives, is characterized by large numbers of very itchy red bumps (papules) that come and go every few days over a period of a month or so. The bumps are usually between 0.2 and 2 cm. in size and some may develop i...

Biotinidase deficiency (BTD) is a treatable, metabolic disorder that is the result of a low concentration, or complete lack, of the enzyme, biotinidase. Biotinidase deficiency is an inherited disorder in which the body is not able to properly proc...

Alkaptonuria is a rare genetic metabolic disorder characterized by the accumulation of homogentisic acid in the body. Affected individuals lack enough functional levels of an enzyme required to breakdown homogentisic acid. Affected individuals may...

Hydrocephalus is a condition characterized by excessive accumulation of fluid in the brain. Hydrocephalus may be congenital or acquired. Communicating hydrocephalus occurs when cerebrospinal fluid (CSF) can still flow amon...

Hyphema is a condition in which there is bleeding in the front chamber of the eye, between the cornea and the iris. It is usually caused by trauma to the eye, such as a blunt force or a sharp object. Symptoms of hyphema include blurred vision, red...

Thyroid disease is particularly common in women of child-bearing age. As a result, it is no surprise that thyroid disease may complicate the course of pregnancy. Frequency varies among different populations and different c...

Chanarin Dorfman syndrome is a rare hereditary disorder of fat (lipid) metabolism. It is characterized by scaly skin (ichthyosis), degeneration of the muscles (myopathy), and abnormal white blood cells with small spaces (vacuoles) filled with fat ...

CHILD syndrome (an acronym for congenital hemidysplasia with ichthyosiform erythroderma and limb defects) is an inherited disorder, affecting primarily women, that is characterized by ichthyosis-like skin abnormalities and limb defects on one side...

Lamellar ichthyosis is a rare genetic skin disorder. In lamellar ichthyosis, the skin cells are produced at a normal rate, but they do not separate normally at the surface of the outermost layer of skin (stratum corneum) and are not shed as quickl...

Erythrokeratolysis hiemalis is an extremely rare form of ichthyosis that was first described in South Africa but has subsequently been identified in other countries. In such cases, a link to South Africa has been determined. The disorder is charac...

Harlequin ichthyosis is a rare genetic skin disorder. The newborn infant is covered with plates of thick skin that crack and split apart. The thick plates can pull at and distort facial features and can restrict breathing and eating. Harlequin inf...

Netherton syndrome is a rare hereditary disorder characterized by scaling skin, hair anomalies, increased susceptibility to atopic eczema (a skin condition that can result in dry, red and flaky skin), elevated IgE levels, and other related symptom...

Sjogren-Larsson syndrome is an inherited disorder characterized by scaling skin (ichthyosis), mental retardation, speech abnormalities, and spasticity. Affected infants develop various degrees of reddened skin with fine scales soon after birth. Af...

Chanarin Dorfman syndrome is a rare hereditary disorder of fat (lipid) metabolism. It is characterized by scaly skin (ichthyosis), degeneration of the muscles (myopathy), and abnormal white blood cells with small spaces (vacuoles) filled with fat ...

General DiscussionPediatric cardiomyopathy is a rare heart condition that affects infants and children. Specifically, cardiomyopathy means disease of the heart muscle (myocardium). Several different types of cardiomyopathy exist and the s...

Idiopathic intracranial hypertension (IIH) is a neurological disorder characterized by increased pressure in the fluid surrounding the brain (cerebrospinal fluid). It is also known as pseudotumor cerebri. Symptoms of IIH include headaches, vision ...

IgA nephropathy (nuh-FROP-uh-thee), also known as Berger's disease, is a kidney disease that occurs when an antibody called immunoglobulin A (IgA) lodges in your kidneys. This results in local inflammation that, over time, may hamper your kidneys'...

The WAS-related disorders are a spectrum of conditions affecting the immune system that are caused by mutations in the WAS gene. These disorders include Wiskott-Aldrich syndrome, X-linked thrombocytopenia and X-linked congenital neutropenia. The W...

Impetigo facts Impetigo is a bacterial infection of the surface of the skin. Impetigo is more common in children than in adults. The two types of impetigo are non-bullous and bullous impetigo. Impetigo ...

Incontinentia Pigmenti (IP) is a rare genetic dermatological disorder affecting the skin, hair, teeth, and central nervous system. Progressive skin changes occur in four stages, the first of which appear in early infancy or can be present at birth...

Congenital generalized fibromatosis (CGF) is a pediatric condition that is often now referred to as "infantile myofibromatosis" (IM). It is characterized by the formation of single or multiple noncancerous (benign) tumors that appear to be derived...

Santavuori disease, a rare genetic disorder, belongs to a group of progressive degenerative neurometabolic diseases known as the neuronal ceroid lipofuscinoses (NCL). These disorders share certain similar symptoms and are distinguished in part by ...

Infant respiratory distress syndrome is a lung disorder that tends to affect premature infants. Major symptoms include difficulty in breathing and collapsed lungs, potentially requiring mechanical ventilation or positive end-expiratory pressure (P...

Inflammatory breast cancer is a rare form of breast cancer. It is typically a very aggressive disease and is called "inflammatory" because the cancer cells block the lymphatic vessels, resulting in changes in the breast (swelling and redness) that...

Insulin is a hormone that is produced by the beta cells of the pancreas. These cells are scattered throughout the pancreas in small clusters known as the islets of Langerhans. The insulin produced is released into the blood stream and travels thro...

Interstitial cystitis facts PBS/IC is an inflammatory disease of the bladder that can cause ulceration and bleeding of the bladder's lining and can lead to scarring and stiffening of the bladder. The symptoms of PBS/IC are...

Intertrigo is a dermatitis that only affects skin folds. Intertrigo is caused when skin is irritated by friction, which is enhanced by moisture and heat. Risk factors for intertrigo include obesity, heat, and humidity....

What is the definition of irritable bowel syndrome (IBS)? Irritable bowel syndrome (IBS) is a gastrointestinal disorder characterized by the presence of a cluster of symptoms and signs in adult or children that include cramping, abdominal ...

Osteonecrosis, also known as avascular necrosis, is a disease resulting from the temporary or permanent loss of the blood supply to the bones. Without blood, the bone tissue dies and causes the bone to collapse. If the process involves the bones n...

Ischemic optic neuropathy (ION) is a condition that affects the optic nerve, which is the nerve that carries visual information from the eye to the brain. It is caused by a decrease in blood flow to the optic nerve, which can be caused by a variet...

Creutzfeldt-Jakob disease (CJD) is an extremely rare degenerative brain disorder (i.e., spongiform encephalopathy) characterized by sudden development of rapidly progressive neurological and neuromuscular symptoms. With symptom onset, affected ind...

Creutzfeldt-Jakob disease (CJD) is an extremely rare degenerative brain disorder (i.e., spongiform encephalopathy) characterized by sudden development of rapidly progressive neurological and neuromuscular symptoms. With symptom onset, affected ind...

Jarcho-Levin syndrome is a rare genetic disorder characterized by distinctive malformations of bones of the spinal column (vertebrae) and the ribs, respiratory insufficiency, and/or other abnormalities. Infants born with Jarcho-Levin syndrome have...

Jessner lymphocytic infiltrate of the skin is an uncommon disorder that is characterized by benign accumulations of lymph cells in the skin. These small lesions are solid, pink or red in color, and appear on the face, neck, and/or back. Skin surro...

Jock itch facts Jock itch is a very common groin rash. Roughly half of jock itch is due to fungus. The remainder is caused by moisture, irritation, and bacterial overgrowth. Symptoms and signs of jock itch includ...

Jock itch, also known as tinea cruris, is a fungal infection that affects the skin of the groin area. It is caused by a type of fungus called dermatophytes, which thrive in warm, moist environments. Jock itch is characterized by red, itchy, and so...

Until recently the relationship of Stevens-Johnson syndrome to other severe blistering disorders was a matter of some debate. Now a consensus seems to be evolving that describes SJS as a rare disorder involving lesions of the mucous membranes alon...

Juvenile Idiopathic Arthritis Uveitis (JIAU) is a type of eye inflammation that is associated with juvenile idiopathic arthritis (JIA). It is a rare condition that affects the uvea, which is the middle layer of the eye. Symptoms of JIAU include re...

Kawasaki's disease facts Kawasaki's disease is a syndrome of unknown cause that mainly strikes young children. Signs of the disease include fever and redness of the eyes, hands, feet, mouth, and tongue. The disea...

Keratitis ichthyosis deafness (KID) syndrome is a rare, genetic, multi-system disorder. It is characterized by defects of the surface of the corneas (keratitis), red, rough thickened plaques of skin (erythrokeratoderma) and sensorineural deafness ...

Erythrokeratolysis hiemalis is an extremely rare form of ichthyosis that was first described in South Africa but has subsequently been identified in other countries. In such cases, a link to South Africa has been determined. The disorder is charac...

Keratosis follicularis, also known as Darier disease, is a rare, genetic skin disorder. Affected individuals develop skin lesions that consist of thickened, rough bumps (papules) or plaques that may also be greasy or have a brown or yellow crust. ...

Haim-Munk syndrome is a rare genetic disorder characterized by the development of red, scaly thickened patches of skin on the palms of the hands and soles of the feet (palmoplantar hyperkeratosis), frequent pus-producing (pyogenic) skin infections...

Keratosis pilaris (KP) facts Keratosis pilaris is a very common, benign skin disorder that affects adolescents and adults. Keratosis pilaris causes numerous small, rough, tan or red little bumps around hair follicles on th...

Seborrheic Keratosis is a skin disorder usually characterized by discolored lesions that appear to be "stuck on" the skin surface. Warts may appear and skin is often oily or greasy. These skin lesions are sometimes mistaken for cancerous growths a...

Keratitis ichthyosis deafness (KID) syndrome is a rare, genetic, multi-system disorder. It is characterized by defects of the surface of the corneas (keratitis), red, rough thickened plaques of skin (erythrokeratoderma) and sensorineural deafness ...

Knee bursitis facts A bursa is a fluid-filled sac that functions as a gliding surface to reduce friction between moving tissues of the body. There are three major bursae of the knee. Bursitis is usually not infec...

Kohler disease is a rare bone disorder of the foot in children that may be the result of stress-related compression at a critical time during the period of growth. It is characterized by limping caused by pain and swelling in the foot. It most oft...

Kohler disease is a rare bone disorder of the foot in children that may be the result of stress-related compression at a critical time during the period of growth. It is characterized by limping caused by pain and swelling in the foot. It most oft...

Kohler disease is a rare bone disorder of the foot in children that may be the result of stress-related compression at a critical time during the period of growth. It is characterized by limping caused by pain and swelling in the foot. It most oft...

Kyphosis facts There are three main types of kyphosis: postural, Scheuermann's, and congenital. Most cases of kyphosis do not require any treatment. Physical therapy and exercise are often effective in postural a...

Latex allergy facts Latex allergy is dramatically on the rise throughout the world. Latex allergy rises with exposure and is suspected to continue to rise until a latex substitute is found. Latex allergy can be s...

Leukoplakia is a condition characterized by thick, white patches that form on the mucous membranes of the mouth and sometimes the throat. These patches are caused by an overgrowth of cells and are often a result of chronic irritation or inflammati...

Granuloma annulare is a chronic degenerative skin disorder. The most common form is localized granuloma annulare, which is characterized by the presence of small, firm red or yellow colored bumps (nodules or papules) that appear arranged in a ring...

Lichen Planus is a rare, recurrent, itchy rash or area of inflammatory eruptions (lesions) of unknown origin characterized by shiny reddish-purple spots on the skin and gray-white ones in the mouth. The disorder may present as itchy spots on the w...

Lichen Planus is a rare, recurrent, itchy rash or area of inflammatory eruptions (lesions) of unknown origin characterized by shiny reddish-purple spots on the skin and gray-white ones in the mouth. The disorder may present as itchy spots on the w...

Papular urticaria, usually called hives, is characterized by large numbers of very itchy red bumps (papules) that come and go every few days over a period of a month or so. The bumps are usually between 0.2 and 2 cm. in size and some may develop i...

Chanarin Dorfman syndrome is a rare hereditary disorder of fat (lipid) metabolism. It is characterized by scaly skin (ichthyosis), degeneration of the muscles (myopathy), and abnormal white blood cells with small spaces (vacuoles) filled with fat ...

Congenital lobar emphysema is a rare respiratory disorder in which air can enter the lungs but cannot escape, causing overinflation (hyperinflation) of the lobes of the lung. It is most often detected in newborns or young infants, but some cases d...

Epidermolysis bullosa (EB) is a genetic skin disorder characterized clinically by blister formation from mechanical trauma. There are four main types with additional sub-types identified. There is a spectrum of severity, and within each type, one ...

Urticaria pigmentosa is a rare skin disorder that is a localized (cutaneous) form of mastocytosis. Some clinicians suggest that urticaria pigmentosa is the childhood form of mastocytosis. Mast cells are specialized cells of connective tissue that ...

General DiscussionRomano-Ward syndrome is an inherited heart (cardiac) disorder characterized by abnormalities affecting the electrical system of the heart. The severity of Romano-Ward syndrome varies greatly from case to case. Some indiv...

Ataxia telangiectasia (AT) is a complex genetic neurodegenerative disorder that may become apparent during infancy or early childhood. The disorder is characterized by progressively impaired coordination of voluntary movements (ataxia), the develo...

Jessner lymphocytic infiltrate of the skin is an uncommon disorder that is characterized by benign accumulations of lymph cells in the skin. These small lesions are solid, pink or red in color, and appear on the face, neck, and/or back. Skin surro...

Alpha-mannosidosis is a rare genetic disorder characterized by a deficiency of the enzyme alpha-D-mannosidase. Alpha-mannosidosis is best thought of as a continuum of disease that is generally broken down into three forms: a mild, slowly progressi...

Macular hole is a small break in the macula, a small spot near the center of the retina that is responsible for sharp, central vision. Macular holes can cause blurred or distorted central vision, and if left untreated, can lead to permanent vision...

Macular pucker is a condition in which the macula, the part of the eye responsible for central vision, becomes wrinkled or distorted. It is caused by the formation of scar tissue on the macula, which can cause blurred or distorted vision. Treatmen...

What is male breast cancer? Men possess a small amount of nonfunctioning breast tissue (breast tissue that cannot produce milk) that is concentrated in the area directly behind the nipple on the chest wall. Like breast cancer in women, can...

What is male breast cancer? Men possess a small amount of nonfunctioning breast tissue (breast tissue that cannot produce milk) that is concentrated in the area directly behind the nipple on the chest wall. Like breast cancer in women, can...

Degos disease is an extremely rare disorder in which small and medium sized arteries become blocked (occlusive arteriopathy), restricting the flow of blood to affected areas. Degos disease usually causes characteristic skin lesions that may last f...

Atypical mole syndrome, also called dysplastic nevus syndrome, is a disorder of the skin characterized by the presence of many mole-like tumors (nevi). Most people have 10-20 moles over their bodies. People with this syndrome often have more than ...

Measles is a highly contagious viral infection that primarily affects children. It is characterized by a red, blotchy rash that typically starts on the face and spreads to the rest of the body. Other symptoms of measles include fever, cough, runny...

Median rhomboid glossitis is a condition characterized by a smooth, red, diamond-shaped lesion on the midline of the dorsal surface of the tongue. It is believed to be caused by a fungal infection, specifically Candida albicans, although other fac...

Melasma facts Melasma is most common in women 20-50 years of age. Melasma looks like brown, tan, or blue-gray spots on the face (hyperpigmentation). Melasma is characterized by three location patterns (central fa...

Erythromelalgia is a rare condition that primarily affects the feet and, less commonly, the hands (extremities). It is characterized by intense, burning pain of affected extremities, severe redness (erythema), and increased skin temperature that m...

Molluscum contagiosum is a common viral skin infection that causes small, raised bumps or lesions on the skin. It is caused by the molluscum contagiosum virus and is highly contagious, spreading through direct skin-to-skin contact or by sharing it...

Marinesco-Sjogren syndrome (MSS) is a rare genetic disorder that affects multiple organ systems of the body. Common symptoms include difficulty coordinating voluntary movements due to degeneration (atrophy) of the cerebellum (cerebellar ataxia), c...

Motor neuron disease comprises a group of severe disorders of the nervous system characterized by progressive degeneration of motor neurons (neurons are the basic nerve cells that combine to form nerves). Motor neurons control the behavior of musc...

Mouth sores, also known as canker sores or aphthous ulcers, are small, painful lesions that develop on the inside of the mouth, including the lips, cheeks, gums, and tongue. They can be white or yellow in color and are often surrounded by a red bo...

Maroteaux-Lamy syndrome is a rare genetic metabolic disorder that belongs to a group of disorders known the mucopolysaccharidoses. The disorder is also known as mucopolysaccharidosis (MPS) type VI. Maroteaux-Lamy syndrome occurs in three types: a ...

Hereditary multiple osteochondromas (HMO) is a rare genetic disorder characterized by multiple benign (noncancerous) bone tumors that are covered by cartilage (osteochondromas), often on the growing end (metaphysis) of the long bones of the legs, ...

Familial adenomatous polyposis (FAP) is a rare inherited cancer predisposition syndrome characterized by hundreds to thousands of precancerous colorectal polyps (adenomatous polyps). If left untreated, affected individuals inevitably develop cance...

Familial adenomatous polyposis (FAP) is a rare inherited cancer predisposition syndrome characterized by hundreds to thousands of precancerous colorectal polyps (adenomatous polyps). If left untreated, affected individuals inevitably develop cance...

Multiple sclerosis (MS) is a disease that causes demyelination (disruption of the myelin that insulates and protects nerve cells) of spinal nerve and brain cells. Although the exact case is unknown, multiple sclerosis is considered ...

Mumps is a contagious viral infection that primarily affects the salivary glands, causing swelling and pain in the cheeks and jaw. It is spread through respiratory droplets, such as coughing or sneezing, and can also be transmitted through close p...

Muscle sprains and strains facts A sprain is abnormal stretching or tearing of a ligament that supports a joint. A strain is abnormal stretching or tearing of a muscle or tendon. Sprains and strains may be caused...

Pain located in the neck is a common medical condition. Neck pain can come from a number of disorders and diseases and can involve any of the tissues in the neck. Examples of common conditions causing neck pain are degenerative disc disease, neck ...

Flesh-eating bacteria (necrotizing fasciitis) is a rare infection of the skin and tissues below it. It can be deadly if not treated quickly. Necrotizing fasciitis spreads quickly and aggressively in an infected person. It causes tissue dea...

Renal cell carcinoma is a form of kidney cancer. Some patients with renal cell carcinoma do not have symptoms (asymptomatic). When symptoms are present, they may include blood in the urine; urine that is brown or rusty-colored; abdominal pain; wei...

Nephrogenic diabetes insipidus (NDI) is a rare kidney disorder that may be inherited or acquired. NDI is not related to the more common diabetes mellitus (sugar diabetes), in which the body does not produce or properly use insulin. NDI is a distin...

Nocardiosis is an infectious pulmonary disease characterized by abscesses in the lungs. These abscesses may extend through the chest wall. The infection is spread through the body via the bloodstream by a microorganism called Nocardia asteroids....

Diabetic Retinopathy is a complication of diabetes and a disorder of the light sensitive tissue of the eye (the retina). This condition is characterized by destructive changes in the blood vessels of the retina, which, if left unchecked, may lead ...

General DiscussionPediatric cardiomyopathy is a rare heart condition that affects infants and children. Specifically, cardiomyopathy means disease of the heart muscle (myocardium). Several different types of cardiomyopathy exist and the s...

Renal glycosuria, also known as renal glucosuria, is a rare condition in which the simple sugar glucose is eliminated (excreted) in the urine despite normal or low blood glucose levels. With normal kidney (renal) function, glucose is excreted in t...

Henoch-Schonlein purpura is a rare inflammatory disease of the small blood vessels (capillaries) and is usually a self-limited disease. It is the most common form of childhood vascular inflammation (vasculitis) and results in inflammatory changes ...

Norrie disease is a rare X-linked disorder that occurs due to errors or disruption (mutations) of the NDP gene. All males are affected by loss of vision present at birth or shortly thereafter. Additional symptoms may occur in some case...

Nystagmus is a condition in which the eyes make repetitive, uncontrolled movements. It can be caused by a variety of conditions, including inner ear problems, vision problems, and neurological disorders. Symptoms may include blurred vision, dizzin...

Ocular melanoma is a rare type of cancer that develops in the cells of the eye. It is the most common primary cancer of the eye in adults, and it can occur in both the iris and the choroid (the layer of tissue between the retina and the sclera). S...

Ocular rosacea is a type of rosacea that affects the eyes. It is characterized by redness, burning, stinging, and itching of the eyes, as well as dryness, sensitivity to light, and the formation of small cysts on the eyelids. In some cases, ocular...

Oculocutaneous albinism (OCA) is a group of rare inherited disorders characterized by a reduced amount or complete lack of melanin pigment in the skin, hair, and eyes. These conditions are caused by mutations in specific genes that are necessary f...

Onchocerciasis, also known as African River Blindness, is a parasitic infection caused by the filarial worm Onchocerca volvulus. It is transmitted to humans through the bite of an infected blackfly. Symptoms of the infection include severe itching...

Optic neuritis is an inflammation of the optic nerve, which is the nerve that carries visual information from the eye to the brain. Symptoms of optic neuritis include sudden vision loss, pain in the eye, and color vision changes. Optic neuritis is...

Oral cysts are fluid-filled sacs or pouches that can develop in the mouth. They can occur in various locations, including the gums, lips, tongue, and roof of the mouth. Oral cysts are typically painless and may go unnoticed until they become large...

An oral fistula is an abnormal connection or passageway that forms between two structures in the mouth, such as between the oral cavity and the skin or between the oral cavity and the nasal cavity. This can result in the leakage of saliva, food, o...

Oral Kaposi sarcoma is a type of cancer that affects the lining of the mouth and throat. It is caused by a virus called human herpesvirus 8 (HHV-8) and is most commonly seen in individuals with weakened immune systems, such as those with HIV/AIDS....

Oral leukoplakia is a condition characterized by thick, white patches or plaques that form on the inside of the mouth, typically on the cheeks, gums, or tongue. These patches cannot be scraped off and may be rough or slightly raised. ...

Oral lichen planus is a chronic inflammatory condition that affects the mucous membranes inside the mouth. It is characterized by the presence of white, lacy patches or sores on the inside of the cheeks, gums, tongue, and other areas of the mouth....

Oral thrush, also known as oral candidiasis, is a fungal infection caused by the overgrowth of Candida albicans in the mouth. It typically appears as white, creamy patches on the tongue, inner cheeks, roof of the mouth, gums, or tonsils. Oral thru...

Oral ulceration refers to the presence of open sores or lesions in the mouth. These ulcers can be painful and may make it difficult to eat, drink, or speak. They can occur on the lips, tongue, gums, inside of the cheeks, or roof of the mouth. Oral...

Oral vesicles are small, fluid-filled blisters that can develop on the inside of the mouth, lips, or tongue. They are often caused by viral infections, such as herpes simplex virus (cold sores) or coxsackievirus (hand, foot, and mouth disease). Or...

Osgood-Schlatter condition (formerly known as Osgood-Schlatter's disease) is a painful condition characterized by tiny, microfractures of the bony bump in the lower leg bone (tibia) where the ligament from the kneecap (patella) is inserted into th...

Osteoarthritis facts Osteoarthritis is a joint inflammation that results from cartilage degeneration. Osteoarthritis can be caused by aging, heredity, and injury from trauma or disease. The most common symptom of...

Osteoarthritis facts Osteoarthritis is a joint inflammation that results from cartilage degeneration. Osteoarthritis can be caused by aging, heredity, and injury from trauma or disease. The most common symptom of...

Erythrokeratolysis hiemalis is an extremely rare form of ichthyosis that was first described in South Africa but has subsequently been identified in other countries. In such cases, a link to South Africa has been determined. The disorder is charac...

Erythrokeratolysis hiemalis is an extremely rare form of ichthyosis that was first described in South Africa but has subsequently been identified in other countries. In such cases, a link to South Africa has been determined. The disorder is charac...

Paget disease of the breast is a form of breast cancer that affects the skin of the nipple. The cause of Paget disease of the breast is poorly understood, but it may be related to tumor cells from other sites in the breast traveling...

Different types of manual therapy, or mobilization, can be used to treat people with spinal alignment problems. For acute musculoskeletal pain, these techniques have been shown to speed recovery. In patients with musculoskeletal disorders ...

Papillitis, also known as optic neuritis, is characterized by inflammation and deterioration of the portion of the optic nerve known as the optic disk. Also referred to as the "blind spot," the optic disk (optic papilla) is that portion of the opt...

Papillon-Lefevre Syndrome (PLS) is an extremely rare genetic disorder that typically becomes apparent from approximately one to five years of age. PLS is characterized by the development of dry scaly patches on the skin of the palms and the soles ...

Papillon-Lefevre Syndrome (PLS) is an extremely rare genetic disorder that typically becomes apparent from approximately one to five years of age. PLS is characterized by the development of dry scaly patches on the skin of the palms and the soles ...

Progressive supranuclear palsy, or PSP, is a rare neurodegenerative disease that is often misdiagnosed as Parkinson's disease because it carries similar symptoms. Because of its rarity, PSP is mostly unknown by the general public....

Pericoronitis is a condition in which the gum tissue around a partially erupted tooth becomes inflamed and infected. This most commonly occurs around the wisdom teeth, which are the last teeth to come in and often do not have enough room to fully ...

Phlebitis refers to inflammation of a vein and it can be caused by any insult to the blood vessel wall, impaired venous flow, or coagulation abnormality. Pain, swelling, redness, and tenderness are some common symptoms of phlebitis....

Phlebitis refers to inflammation of a vein and it can be caused by any insult to the blood vessel wall, impaired venous flow, or coagulation abnormality. Pain, swelling, redness, and tenderness are some common symptoms of phlebitis....

Photokeratitis is a painful eye condition caused by exposure to ultraviolet (UV) radiation. It is sometimes referred to as "snow blindness" or "welder's flash." Symptoms of photokeratitis include redness, tearing, pain, and temporary vision loss. ...

Phthisis, also known as pulmonary tuberculosis, is one of the most common illnesses that humans face. It affects people of all ages, from all walks of life, and in every country.  While phthisis may affect almost every organ in...

Incontinentia Pigmenti (IP) is a rare genetic dermatological disorder affecting the skin, hair, teeth, and central nervous system. Progressive skin changes occur in four stages, the first of which appear in early infancy or can be present at birth...

Pilonidal cyst facts Pilonidal cysts are fluid-filled sacs that form at the top of the crease of the buttocks above the sacrum. A painful abscess can form if the cyst and the overlying skin become infected. Pilonidal cysts...

Pineal cysts are benign (non-cancerous) fluid-filled sacs located in the region of the brain that contains the pineal gland. Small pineal cysts (.5 cm or smaller) are common occurrences, often found incidentally on routine neurological exams. Smal...

Pinguecula and Pterygium are two common eye conditions that affect the conjunctiva, the thin, transparent membrane that covers the white part of the eye and the inner surface of the eyelids. A Pinguecula is a yellowish, slightly raised bump on the...

Placenta previa is the attachment of the placenta to the wall of the uterus in a location that completely or partially covers the uterine outlet (opening of the cervix). Bleeding after the 20th week of gestation is the main symptom ...

Posterior vitreous detachment (PVD) is a condition in which the vitreous gel, which is a clear gel that fills the inside of the eye, separates from the retina. This separation can cause flashes of light, floaters, or a curtain-like effect in the v...

Psoriasis facts Psoriasis is a chronic inflammatory skin disease. Patients with psoriasis tend to be obese and are predisposed to diabetes and heart disease. Psoriasis can be initiated by certain environmental tr...

Pump lung, (also known as Shock Lung), is inflammatory lung damage.  Pump lung is caused by fluid buildup in the lungs' small air sacs (called alveoli), which makes breathing very difficult. It also results in severely low bloo...

Infectious arthritis is an inflammation of one or more joints that occurs as a result of infection by bacteria, viruses or, less frequently, fungi or parasites. The symptoms of Infectious arthritis depend upon which agent has caused the infection ...

Infectious arthritis is an inflammation of one or more joints that occurs as a result of infection by bacteria, viruses or, less frequently, fungi or parasites. The symptoms of Infectious arthritis depend upon which agent has caused the infection ...

Pyogenic granuloma is a common type of non-cancerous skin growth that is typically small, red, and raised. It is also known as lobular capillary hemangioma. Pyogenic granulomas can develop on the skin or mucous membranes, such as the gums. They ar...

A ranula is a type of cyst that forms on the floor of the mouth, usually under the tongue. It is typically filled with mucus and can cause swelling and discomfort. Ranulas are usually harmless, but they can sometimes become infected or grow large ...

Retinal artery occlusion is a condition in which the blood supply to the retina is blocked. This can be caused by a clot, plaque, or other obstruction in the artery. Symptoms of retinal artery occlusion include sudden vision loss, eye pain, and se...

Retinitis Pigmentosa (RP) is a group of inherited eye diseases that cause progressive vision loss. It is caused by a genetic mutation that affects the light-sensitive cells in the retina, which are responsible for converting light into signals tha...

Retinoblastoma is a rare form of eye cancer that affects the retina, the light-sensitive tissue at the back of the eye. It is most commonly found in children under the age of five, and is caused by a genetic mutation. Symptoms of retinoblastoma in...

Retinopathy of prematurity (ROP) is a potentially blinding eye disorder that affects premature babies. It is caused by abnormal blood vessel growth in the retina, the light-sensitive tissue at the back of the eye. ROP can lead to retinal detachmen...

Familial dysautonomia is a rare genetic disorder of the autonomic nervous system (ANS) that primarily affects people of Eastern European Jewish heritage. It is characterized by diminished sensitivity to pain, lack of overflow tearing in the eyes, ...

Ringworm, also known as tinea, is a common fungal infection of the skin that can affect different parts of the body, including the scalp, feet, groin, and nails. Despite its name, ringworm is not caused by a worm but by various types of fungi that...

Toxic epidermal necrolysis (TEN) is a rare, sometimes life-threatening unless properly treated, immunological disorder of the skin. It is characterized by blisters that meld into one another to cover a substantial portion of the body (30% and more...

Rosacea (roe-ZAY-she-uh) is a common skin condition that causes redness and visible blood vessels in your face. It may also produce small, red, pus-filled bumps. These signs and symptoms may flare up for a period of weeks to months and then dimini...

Russell-Silver syndrome (RSS) is a rare disorder characterized by intrauterine growth retardation and postnatal growth deficiency along with a handful of common physical characteristics and a range of other symptoms. The wide spectrum of phenotype...

Frey syndrome is a rare disorder that most often occurs as a result of surgery in the area near the parotid glands. The parotid glands are the largest salivary glands in the body located just below the ears on either side of the face. The main sym...

Sandhoff disease is a lipid storage disorder characterized by a progressive deterioration of the central nervous system. The clinical symptoms of Sandhoff disease are identical to Tay-Sachs disease. Sandhoff disease is an autosomal recessive genet...

Scabies is a highly contagious skin infestation caused by the microscopic mite Sarcoptes scabiei. It is characterized by intense itching and a pimple-like rash. Scabies is usually spread through close physical contact with an infected person, and ...

Toxic epidermal necrolysis (TEN) is a rare, sometimes life-threatening unless properly treated, immunological disorder of the skin. It is characterized by blisters that meld into one another to cover a substantial portion of the body (30% and more...

Though they're not cancerous, sebaceous cysts can be irritating. A sebaceous cyst is a small lump or bump under the skin. This type of cyst is not cancerous. They are most often found on the face, neck, upper back, and upper chest,...

Seborrheic dermatitis facts Seborrheic dermatitis is probably the single most common inflammatory skin condition affecting humans aside from acne vulgaris. Seborrheic dermatitis is highly treatable but incurable. ...

Shingles is a medical condition that is caused by the reactivation of the chickenpox-causing virus in the body. Shingles are extremely painful but it isn’t life-threatening.  Shingles is a painful rash that occurs anywher...

Bloom syndrome is a rare genetic disorder characterized by short stature; increased sensitivity to light (photosensitivity); multiple small dilated blood vessels on the face (facial telangiectasia), often resembling a butterfly in shape; immune de...

Sialadenitis is a condition characterized by inflammation of the salivary glands, which are responsible for producing saliva in the mouth. This inflammation can be caused by bacterial or viral infections, blockages in the salivary ducts, autoimmun...

Squamous cell carcinoma (SCC) is the second most common skin cancer with between 200,000 and 250,000 cases reported each year. It is a malignant cancer that usually develops from the epidermis and/or the mucous lining of the body cavities (epithel...

Skin tag facts Skin tags are very common but harmless small, soft skin growths. Skin tags tend to occur on the eyelids, neck, armpits, groin folds, and under breasts. One person may have anywhere from one to over...

Smallpox facts Smallpox is a contagious disease caused by the variola virus. Smallpox was the first disease to be eliminated from the world through public-health efforts and vaccination. Smallpox still poses a th...

Sneddon syndrome is a rare progressive disorder affecting the blood vessels characterized by the association of a skin condition and neurological abnormalities. Characteristics include multiple episodes of reduced blood flow to the brain (cerebral...

Familial idiopathic basal ganglia calcification (FIBGC) is a rare neurological disorder characterized by the presence of abnormal calcium deposits (calcifications) of unknown cause. Associated symptoms include progressive deterioration of cognitiv...

Diffuse idiopathic skeletal hyperostosis (DISH), also known as Forestier's disease, affects the ligaments around the spine. Sections of the ligaments turn into bone in this disorder, which is considered to be a form of degenerative arthritis. ...

Spinal headaches are a fairly common complication in those who undergo a spinal tap (lumbar puncture) or spinal anesthesia. Both procedures require a puncture of the membrane that surrounds the spinal cord and, in the lower spine, the lumbar and s...

Billions of people worldwide carry the Staphylococcus aureus bacteria, but most are unaffected by it. There are more than 30 different types of bacteria that are classified as Staphylococcus; the most common is Staphylococcus aureus. ...

Stickler Syndrome is a genetic disorder that affects the connective tissues in the body. It is caused by a mutation in one of several genes, and it can cause a variety of symptoms, including hearing loss, vision problems, joint pain, and skeletal ...

Stomatitis is a general term for inflammation of the mucous lining of the mouth, which can result in painful sores or ulcers. It can be caused by a variety of factors, including viral or bacterial infections, autoimmune disorders, allergies, or ir...

Strabismus, commonly known as crossed eyes, is a condition in which the eyes are not properly aligned with each other. It is caused by a lack of coordination between the extraocular muscles, which control the movement of the eyes. Strabismus can c...

Stretch mark facts The medical name for stretch marks is striae distensae. Stretch marks are very common. Stretch marks rarely are a sign of a significant medical problem. Stretch marks are generally pa...

Creutzfeldt-Jakob disease (CJD) is an extremely rare degenerative brain disorder (i.e., spongiform encephalopathy) characterized by sudden development of rapidly progressive neurological and neuromuscular symptoms. With symptom onset, affected ind...

Subconjunctival hemorrhage is a condition in which small blood vessels in the white part of the eye (the sclera) break and leak blood. It is usually painless and causes the white of the eye to appear red or pink. It is a common condition that is u...

Reflex sympathetic dystrophy syndrome (RSDS), also known as complex regional pain syndrome, is a rare disorder of the sympathetic nervous system that is characterized by chronic, severe pain. The sympathetic nervous system is that part of the auto...

Introduction The superior vena cava is a large vein located in the upper chest, which collects blood from the head and arms and delivers it back to the right atrium of the heart. If this vein is compressed by outside structures, or if a th...

Susac's syndrome is a rare disorder characterized by three main problems: impaired brain function (encephalopathy), partial or complete blockage (occlusion) of the arteries that supply blood to the retina (branch retinal artery occlusion, or BRAO)...

Sweet syndrome is a rare skin disorder characterized by fever, inflammation of the joints (arthritis), and the sudden onset of a rash. The rash consists of bluish-red, tender papules that usually occur on the arms, legs, face or neck, most often o...

General DiscussionBuerger's disease, also known as thromboangiitis obliterans, is a rare disorder that, in most cases, affects young or middle-aged male cigarette smokers. It is characterized by narrowing or blockage (occlusion) of the ve...

What are yeast infections? What are commonly known as "yeast" infections are caused by various species of a yeast-like fungus called Candida, particularly the species Candida albicans. Yeast organisms are part of the germs (including bacte...

Tinea versicolor is a common fungal infection of the skin. The fungus interferes with the normal pigmentation of the skin, resulting in small, discolored patches. These patches may be lighter or darker in color than the surrounding skin and most c...

TORCH Syndrome refers to infection of a developing fetus or newborn by any of a group of infectious agents. "TORCH" is an acronym meaning (T)oxoplasmosis, (O)ther Agents, (R)ubella (also known as German Measles), (C)ytomegalovirus, and (H)erpes Si...

Cervical dystonia, also known as spasmodic torticollis, is a rare neurological disorder characterized by involuntary muscle contractions in the neck that cause abnormal movements and postures of the neck and head. In some cases, these abnormal con...

Toxoplasmosis is an infection caused by a single-celled parasite called Toxoplasma gondii. The infection is most commonly acquired from contact with cats and their feces or with raw or undercooked meat. The U.S. Centers for Disease Control...

Toxoplasmosis is an infection caused by the parasite Toxoplasma gondii. It is most commonly spread through contact with infected cat feces, but can also be spread through contaminated food or water, or from mother to baby during pregnancy. Symptom...

Grover's disease is a rare, transient skin disorder that consists of small, firm, raised red lesions, most often on the skin of the chest and back. Diagnosis of this disorder becomes apparent under microscopic examination when the loss of the "cem...

Trichiasis is a condition in which the eyelashes grow inwards, towards the eye, instead of outwards. This can cause irritation, pain, and even vision loss if left untreated. Treatment typically involves electrolysis or laser surgery to remove the ...

Trichomoniasis is a common sexually transmitted infection caused by a parasite. In women, trichomoniasis can cause a foul-smelling vaginal discharge, genital itching and painful urination. Men who have trichomoniasis typically have no symp...

Trichomoniasis is a sexually transmitted infection (STI) caused by a parasite called Trichomonas vaginalis. It is one of the most common STIs worldwide and can affect both men and women. Symptoms of trichomoniasis can include genital itching, burn...

Trichomoniasis is a common sexually transmitted infection caused by a parasite. In women, trichomoniasis can cause a foul-smelling vaginal discharge, genital itching and painful urination. Men who have trichomoniasis typically have no symp...

Trichorhinophalangeal syndrome type II (TRPS2), also known as Langer-Giedion syndrome, is an extremely rare inherited multisystem disorder. TRPS2 is characterized by fine, thin hair; unusual facial features; progressive growth retardation resultin...

Trichorhinophalangeal syndrome type III (TRPS3), also known as Sugio-Kajii syndrome, is an extremely rare inherited multisystem disorder. TRPS3 is characterized by fine, thin light-colored hair; unusual facial features; abnormalities of the finger...

Type 1 diabetes, once known as juvenile diabetes or insulin-dependent diabetes, is a chronic condition in which the pancreas produces little or no insulin. Insulin is a hormone needed to allow sugar (glucose) to enter cells to produce energy. ...

Gilbert syndrome is a mild genetic liver disorder in which the body cannot properly process bilirubin, a yellowish waste product that is formed when old or worn out red blood cells are broken down (hemolysis). Individuals with Gilbert syndrome hav...

Cholinergic urticaria is a relatively common disorder of the immune system characterized by an immediate skin reaction (hypersensitivity) to heat, emotional stress, and/or exercise. Symptoms of the disorder include the appearance of distinctive sm...

Physical urticaria is a condition in which red (erythematous) allergic skin lesions and itching (pruritus) are produced by exposure to heat, cold, or contact with chemicals or plants. These are called wheals by the medical community and may range ...

Uveitis is inflammation of the 'uvea' of the eye. The uvea is made up of three parts. The first part is the iris, which is the colored ring of tissue you can see in the mirror. The dark hole in the middle of the iris is the pupil. The second and t...

Uveitis is an inflammation of the uvea, the middle layer of the eye that contains the blood vessels, iris, and ciliary body. It can cause pain, redness, and blurred vision. Uveitis can be caused by infection, injury, or autoimmune diseases. Treatm...

General DiscussionVACTERL association is a nonrandom association of birth defects that affects multiple median and para-median structures. The term VACTERL is an acronym with each letter representing the first letter of one of the more co...

General DiscussionVACTERL association is a nonrandom association of birth defects that affects multiple median and para-median structures. The term VACTERL is an acronym with each letter representing the first letter of one of the more co...

Cutis marmorata telangiectatica congenita (CMTC) is a rare inherited disorder characterized by discolored patches of skin caused by widened (dilated) surface blood vessels. As a result, the skin has a purple or blue "marbled" or "fishnet" appearan...

Nephrogenic diabetes insipidus (NDI) is a rare kidney disorder that may be inherited or acquired. NDI is not related to the more common diabetes mellitus (sugar diabetes), in which the body does not produce or properly use insulin. NDI is a distin...

Joubert syndrome is an autosomal recessive genetic disorder that affects the area of the brain that controls balance and coordination. This condition is characterized by a specific finding on an MRI called a "molar tooth sign" in which the cerebel...

Primary visual agnosia is a rare neurological disorder characterized by the total or partial loss of the ability to recognize and identify familiar objects and/or people by sight. This occurs without loss of the ability to actually see the object ...

Best vitelliform macular dystrophy is an autosomal dominant genetic form of macular degeneration that usually begins in childhood or adolescence and slowly progresses to affect central vision. The age of onset and severity of vision loss are highl...

Neurofibromatosis type 1 (NF1), also called von Recklinghausen's disease, is a rare genetic disorder characterized by the development of multiple noncancerous (benign) tumors of nerves and skin (neurofibromas) and areas of abnormally decreased or ...

Neurofibromatosis type 1 (NF1), also called von Recklinghausen's disease, is a rare genetic disorder characterized by the development of multiple noncancerous (benign) tumors of nerves and skin (neurofibromas) and areas of abnormally decreased or ...

Lichen sclerosus is a chronic skin disorder that most commonly affects post-menopausal women. However, it is sometimes identified among pre-menopausal women, and, even more rarely, among males. When found in males, the disease is known as balaniti...

In ichthyosis vulgaris, the skin cells are produced at a normal rate, but they do not shed normally at the surface of the outermost layer of skin (stratum corneum) and are not shed as quickly as they should be. The result is a build-up of scale. F...

Weil syndrome, a rare infectious disorder, is a severe form of the bacterial infection caused by Leptospira bacteria known as leptospirosis. Weil syndrome is characterized by dysfunction of the kidneys and liver, abnormal enlargement of the liver ...

Familial eosinophilic cellulitis is a rare skin disorder. It is characterized by raised, red, swollen, and warm areas of skin, in a flame-shaped pattern with associated pain. The exact cause of the disease is unknown. However, bites of spiders, be...

Wildervanck syndrome, also known as cervicooculoacoustic syndrome, is a rare genetic disorder that primarily affects females. The disorder is characterized by a skeletal condition known as Klippel-Feil syndrome (KFS); abnormalities of certain eye ...

The WAS-related disorders are a spectrum of conditions affecting the immune system that are caused by mutations in the WAS gene. These disorders include Wiskott-Aldrich syndrome, X-linked thrombocytopenia and X-linked congenital neutropenia. The W...

MCT8-specific thyroid hormone cell transporter deficiency (THCT deficiency) is an inherited disorder that is characterized by severe mental retardation, an impaired ability to speak, diminished muscle tone (hypotonia), and/or movement abnormalitie...

L1 syndrome is an inherited, X-linked disorder occurring in males that primarily affects the nervous system. The disease is mainly characterized by hydrocephalus (increased fluid in the center of the brain), spasticity of the lower limbs (muscle s...

De Sanctis-Cacchione syndrome is an extremely rare disorder characterized by the skin and eye symptoms of xeroderma pigmentosum (XP) occurring in association with neurological abnormalities, mental retardation, unusually short stature (dwarfism), ...

Yeast infection, also known as candidiasis, is a fungal infection caused by an overgrowth of the Candida fungus. It can occur in various parts of the body, including the mouth, throat, skin, and genital area. Symptoms of yeast infection may includ...