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 ...

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...

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...

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...

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...

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...

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...