Hidradenitis suppurativa, a severe form of acne, affects the apocrine sweat glands as well as the sebaceous (oil) glands located in the genital area and armpits. These aren't tiny zits -- we're talking clusters of blackheads, painful lesions and large cysts. The lesions may leak pus and remain open sores, resulting in scars. The cysts sometimes burst due to the pressure and skin-on-skin contact, draining pus and developing into open wounds that are difficult to heal. The bumps and lesions can last for months or years and cause serious skin infections.
Hidradenitis suppurativa typically begins at puberty, when sweat and oil production both ramp up. These fluids, along with dead skin cells, become trapped in the pores and hair follicles, leading to serious inflammation. We don't know exactly what causes this extreme acne, but it can be triggered by excessive sweat and oil production as well as other factors like obesity and stress. Women are more likely than men to develop it, and often have flare-ups around their menstrual cycle. It may also have a genetic component.
The most extreme treatment for this type of acne requires removing the affected skin completely and replacing it with a skin graft from elsewhere on the body, but that's a last resort. Antibiotics, steroids and medications to slow down or stop oil production in the affected area are the first line of treatment. Deep cysts may need to be lanced and drained.