Hidradenitis suppurativa, also known as HS and less commonly as acne inversa, is a chronic, noncontagious, inflammatory condition characterized by painful bumps or boils and tunnels in and under the skin. Pus-filled bumps on the skin or hard bumps beneath the skin can progress to painful, inflamed areas (also called “lesions”) with chronic drainage. HS starts in the hair follicle in the skin. In most cases, the cause of the disease is unknown, although a combination of genetic, hormonal, and environmental factors likely play a role in its development. The disease can significantly affect a person’s quality of life.