Hidradenitis suppurativa affects the apocrine-bearing areas of the skin. The onset is variable but usually occurs in the second and third decades of life, coinciding with development of the apocrine glands. The condition is characterised by painful, inflammatory papules and nodules which frequently progress to form abscesses, sinus tracts and hypertrophic scars. Bacteria are not felt to have a primary role in lesion formation, and abscesses are often sterile. The diagnosis of hidradenitis suppurativa is clinically based, without a specific diagnostic test. The most important non-genetic factors implicated in hidradenitis suppurativa are obesity and smoking. Locally recurring lesions can be treated surgically and more widespread disease may be better managed with a combination of medical treatment and surgery.