Hidradenitis suppurativa (HS) is a skin condition that causes small, painful acne-like lumps to form under the skin. Hidradenitis suppurativa is commonly found in areas where skin rubs against skin, such as the armpits, inner thighs, or near the groin, buttocks, or breasts.
Hidradenitis suppurativa is often mistaken for pimples, boils, or acne cysts. Without treatment, these lumps can become more painful, produce a foul-smelling discharge, leak blood or pus, and create scarring. Over time, tunnels known as sinus tracts can form under the skin. These tunnels can trap bacteria and sweat under the skin, leading to chronic infection and inflammation.
The pain and discharge of HS can be debilitating; the skin condition can impair the quality of life more than psoriasis and atopic dermatitis.