Pilonidal sinus - Disorders of the rectum and anus

Pilonidal sinus

Definition

A sinus of the natal cleft containing hair that often becomes infected.

Aetiology/pathophysiology

It is thought that sinuses arise from penetration of hairs subcutaneously with secondary infection. A post anal pilonidal sinus typically occurs around 2 cm posterior to the anus and extends superiorly and subcutaneously for about 2–5 cm.

Clinical features

The sinus only becomes symptomatic when infection causes an abscess with swelling, tenderness and discharge.

Management

Abscesses are drained, deroofed and cleaned under general anaesthetic. The cavity is left open to granulate. Pilonidal sinuses tend to recur.