Pilonidal disease is a skin infection in the natal cleft (the cleavage in the midline between the buttocks). This area is close to the anus and therefore can be difficult to treat as it is often difficult to keep the wound clean. Pilonidal disease is a result of hairs inserted into the skin of the natal cleft and embedded under the skin. This may lead to infection and abscesses with underlying tracts.

The prevalence of pilonidal disease is 26 in 100,000 people in developed countries. The affected age group is usually between teenage years and 40 years old.

The symptoms of pilonidal disease vary from no symptoms, small abscesses, discharging pits to a painful large mass (abscess).

Pilonidal disease can manifest as pilonidal abscess or pilonidal sinus. Many patients with pilonidal disease develop an abscess that is painful. It usually discharges pus spontaneously if it is not drained surgically in time. Pilonidal sinus is the condition whereby there are a number of pits in the natal cleft. The sinuses can be asymptomatic in some people. In others, they can give rise to pus discharge and abscess.

Treatment of pilonidal disease depends on the condition of the disease (acute or chronic) and locations of the pits and abscesses. A pilonidal abscess can be treated via an incision and drainage. However, a definitive operation to remove all the sinuses and the underlying hairs and infection will require a full excision of the involved tissues. The resulting defect is then filled with some form of flap. The flaps used may include Karydakis advancement flap, Z-plasty, and rhomboid rotational flap. Some surgeons do not excise the infected area but used an incision beside the area to clean the underlying cavity via this incision. This procedure is known as Bascom's operation. Please consult your surgeon for the procedure that he/she performs. Each surgeon has his/her own preference and a higher success rate associated with the procedure that he/she uses frequently.