Pilonidal Sinus

What is a pilonidal sinus?

A pilonidal sinus is a small tunnel or tract that forms underneath the skin. It occurs in the midline buttock cleft from the region of the coccyx to the lower back. The tract always starts from a midline pit and will tunnel off to one side.

The tracts can be multiple and are filled with hair, debris and pus.

Why does it happen?

No one knows the exact cause of a pilonidal sinus. It is more common in males and typically occurs from late teens to thirties. A pilonidal sinus likely develops through a combination of hair growth and friction. Hairs are forced in to the sinus tracts creating an inflammatory reaction resulting in a cyst or abscess.

What are the symptoms?

The most common symptom is a bloody purulent discharge from the sinus opening. Often people are not aware that a pilonidal sinus is developing until it suddenly turns in to an abscess. Pilonidal sinuses can also cause pain.

What is the treatment of a pilonidal sinus?

Usually once a pilonidal sinus is recognised it is causing problems and will likely need surgery. The type of surgery will differ depending on whether it is performed electively or as an emergency.

Elective excision

If there is no significant abscess component to the sinus then it can usually undergo an elective excision and closure of the wound. There are various methods for excising a pilonidal sinus from a simple excision to a more complex skin flap. The choice of operation will be determined by the position and number of midline pits and the orientation of the sinus tracts.

Emergency drainage

The first some people know about a pilonidal sinus is when it suddenly becomes infected and forms an abscess. This usually requires surgery to drain the abscess. When it is infected, the wound is best left open and packed with dressings. These dressings will usually be continued once out of hopsital and the wound can take several weeks to heal.