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 ...

Familial lipoprotein lipase (LPL) deficiency is a rare genetic metabolic disorder characterized by a deficiency of the enzyme lipoprotein lipase. Deficiency of this enzyme prevents affected individuals from properly digesting certain fats and resu...

Celiac disease, sometimes called celiac sprue or gluten-sensitive enteropathy, i...

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. ...

Cryptococcus is a fungus that is found in soil all over the world, usually in association with bird droppings. Cryptococcus neoformans is the most common Cryptococcus species that causes illness in humans. Cryptococcus gattii, a less common specie...

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...

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...

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...

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...

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...