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...

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 ...

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...

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...

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. ...

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. ...

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...

Dermatitis herpetiformis, also known as Duhring disease, is a rare, chronic, skin disorder characterized by the presence of groups of severely itchy (pruritic) blisters and raised skin lesions (papules). These are more common on the knees, elbows,...

Dupuytren's contracture facts A Dupuytren's contracture is a localized scar tissue formation in the palm. The precise cause of a Dupuytren's contracture is not known. A Dupuytren's contracture is sometimes inheri...

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. ...

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. ...

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...

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...

Folliculitis facts Folliculitis is a very common, benign skin disorder that appears as pinpoint red bumps sometimes with a small dot of pus at the top. Folliculitis affects people of all ages, from babies to seniors. ...

Fox-Fordyce disease is a rare skin disorder that primarily affects women. The disorder is characterized by intense itching especially in the underarm area, the pubic area and around the nipples. In Fox-Fordyce disease abnormalities affecting the a...

Genital warts are a sexually transmitted infection caused by the human papillomavirus (HPV). They are small, flesh-colored bumps or growths that appear on or around the genital area. Genital warts can be spread through sexual contact and are highl...

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...

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...

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...

Heat rash facts Heat rash occurs when the skin's sweat glands are blocked and the sweat produced cannot get to the surface of the skin to evaporate. This causes inflammation that results in a rash. Common symptoms of heat ...

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...

Histoplasmosis is an infection caused by the fungus Histoplasma. The fungus can be found in the environment, particularly in soil with a high concentration of bird or bat droppings. Histoplasma is mostly found in the central and eastern United Sta...

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...

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...

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...

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 ...

Molluscum contagiosum facts A viral infection of the skin causes molluscum contagiosum, a mild skin disease. Risk factors include direct and indirect contact with an infected person's skin. Symptoms include painl...

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...

Idiopathic nodular panniculitis is a rare spectrum of skin disorders characterized by single or multiple, tender or painful bumps below the surface of the skin (subcutaneous nodules) that usually lead to inflammation of the subcutaneous layer of f...

Idiopathic nodular panniculitis is a rare spectrum of skin disorders characterized by single or multiple, tender or painful bumps below the surface of the skin (subcutaneous nodules) that usually lead to inflammation of the subcutaneous layer of f...

Idiopathic nodular panniculitis is a rare spectrum of skin disorders characterized by single or multiple, tender or painful bumps below the surface of the skin (subcutaneous nodules) that usually lead to inflammation of the subcutaneous layer of f...

Penile cancer is a disease in which malignant (cancer) cells form in the tissues of the penis. The penis is a rod-shaped male reproductive organ that passes sperm and urine from the body. It contains two types of erectile tissue (spongy ti...

Penile cancer is a disease in which malignant (cancer) cells form in the tissues of the penis. The penis is a rod-shaped male reproductive organ that passes sperm and urine from the body. It contains two types of erectile tissue (spongy ti...

Pityriasis rosea facts Pityriasis rosea begins as a single, large pink patch found on the trunk called the "herald patch." The herald patch is followed one to two weeks later with smaller pink patches in a "Christmas tree"...

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...

Scabies is an itchy, highly contagious skin disease caused by an infestation by the itch mite Sarcoptes scabiei. Direct skin-to-skin contact is the mode of transmission. A severe and relentless itch is the predominant symp...

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 ...

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...

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...

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...

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...

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...