Pilonidal disease is an infection caused by a hair that injures the skin at the top of the cleft between the buttocks.

A pilonidal abscess is a collection of pus at the infection site. A pilonidal sinus is a chronic draining wound at the site.

Pilonidal disease usually occurs in young, hairy, white men but can also occur in women. A pilonidal sinus can cause pain and swelling. To distinguish pilonidal disease from other infections, a doctor looks for pits—tiny holes in or next to the infected area.

Generally, a pilonidal abscess must be cut and drained by a doctor. Usually, a pilonidal sinus must be removed surgically.

Last full review/revision October 2007 by Parswa Ansari, MD; Norman Sohn, MD