Hidradenitis suppurativa

http://www.aocd.org/skin/dermatologic_diseases/hidradenitis_suppu.html
http://www.mayoclinic.com/health/hidradenitis-suppurativa/ds00818

Hidradenitis Suppurativa

Hidradenitis suppurativa, also known as acne inversa, is a chronic, often debilitating disease primarily affecting the axillae, perineum, and inframammary regions. Prevalence rates of up to 4% have been estimated. Our understanding of the disease has changed over time. It is now considered a disease of follicular occlusion rather than an inflammatory or infectious process of the apocrine glands. Clinically, the disease often presents with tender subcutaneous nodules beginning around puberty. The nodules may spontaneously rupture or coalesce, forming painful, deep dermal abscesses. Eventually, fibrosis and the formation of extensive sinus tracts may result. The location of the lesions may lead to social embarrassment and the failure to seek medical treatment. Therapies in the past have consisted of long-term antibiotics, antiandrogens, and surgery. New treatments like tumor necrosis factor-alfa inhibitors have given clinicians more options against this difficult disease.

From: http://www.ncbi.nlm.nih.gov/pubmed/19293006