Hidradenitis Suppurativa or HS is a poorly studied skin disease that affects areas bearing apocrine sweat glands and hair follicles; such as the underarms, groin and buttocks, and under the breasts in women.

The disease manifests as clusters of chronic abscesses, often as large as baseballs, that are extremely painful to the touch and may persist for years with occasional to frequent periods of inflammation, culminating in drainage, often leaving open wounds that will not heal. Drainage provides some relief from severe, often debilitating, pressure pain. These flare-ups are often triggered by stress, hormonal changes, or humid heat. Persistent lesions may lead to the formation of sinus tracts, or tunnels connecting the abscesses under the skin. At this stage, complete healing is usually not possible, and progression of the disease in the area is inevitable. Occurrences of bacterial infections and cellulitis (deep tissue inflammation) are likely at these sites. HS pain is difficult to manage.

HS often goes undiagnosed for years because patients are ashamed to speak with anyone. When they do see a doctor, the disease is frequently misdiagnosed or prescribed treatments are ineffective, temporary and sometimes even harmful. There is no known cure nor any consistently effective treatment.