A pilonidal sinus is a skin condition of the natal cleft, the area between the muscles of the buttocks. Strands of hair sit beneath the level of the skin causing inflammation. Patients will notice abscesses with acute pain or chronic discharge of pus from openings in the skin. Attacks of inflammation will often settle spontaneously but antibiotics may hasten this process.

The hair is usually derived from the skin of the buttocks and lower back. The condition is more common in hairy people and males. Removal of hair can be effective at reducing recurrent disease.

For patients with an acute pilonidal abscess, incision and drainage with debridement of all the hair debris from the sinus may be curative. More complicated disease with a network of sinus or hair containing sinuses often requires more extensive surgery. There are many techniques described for this condition and the success rates vary. The common theme for the surgery is that the midline pits and the hair filled sinuses must be excised and the associated pus and infection debrided. The wound may then be closed with flaps, by secondary intention, or with the use of vacuum dressings.

Some patients do not need surgery and instead their pilonidal sinus symptoms can be treated with regimes of hair removal and local hygiene. With time, the skin of the natal cleft can mature and while the midline pits remain, inflammation becomes less frequent and may indeed stop.

Overall, patients with pilonidal sinus disease need assessment to determine whether their symptoms are frequent and severe enough to warrant surgery. If required, surgery must remove all of the inflamed and infected skin and then allow healthy skin to heal in the place of the pilonidal sinus midline pits. The technique of closure will depend on the extent of disease.