A pilonidal sinus is a small tunnel that forms under the skin at the top of the buttock crease, near the tailbone. It usually contains hair and skin debris, and it tends to affect young men who sit for long hours — drivers, students and office workers being common examples. Left alone, it can keep getting infected and become a recurring problem.
What is a pilonidal sinus?
The word "pilonidal" means a nest of hair. In this condition, loose hairs work their way into the skin in the sacrococcygeal area — where the buttocks meet. The body treats the hair as foreign material, which can cause a local infection and form a small sinus (tunnel) under the skin. It is not caused by poor hygiene alone, but hygiene and friction play a part. A pilonidal sinus can be:
- Asymptomatic — present with no symptoms, found during an examination.
- Infected — causing a painful swelling, often with pus discharge.
- Recurrent — returning again and again after each episode settles.
Symptoms of a pilonidal sinus
- Pain or tenderness near the tailbone, especially when sitting.
- Swelling and redness at the top of the buttock crease.
- Pus or blood-stained discharge from one or more small openings.
- Recurrent infections that flare up, drain and then settle.
- Occasional fever or discomfort when the infection is active.
What causes a pilonidal sinus?
- Loose hairs penetrating the skin of the buttock crease.
- Friction from sitting, tight clothing or body hair.
- Prolonged sitting — common in drivers, students and desk workers.
- Poor local hygiene and excessive sweating.
- Being overweight, which deepens the crease and raises pressure.
Treatment for a pilonidal sinus
Managing infection first
- Antibiotics for the active infection, as prescribed by a doctor.
- Drainage of an abscess that has formed, to release pus and pain.
- Warm baths and keeping the area clean and dry.
Definitive treatment
- Pit-picking — a small, minimally invasive procedure that clears the sinus pits and hair.
- Minimally invasive techniques — removing the tract and its contents while leaving healthy skin intact, so healing is faster.
- Excision — surgical removal of the sinus and affected skin for more severe or recurring cases, followed by good aftercare.
Whatever procedure is chosen, the key to a lasting result is careful aftercare — keeping the area clean, dry and free of hair while it heals.
Prevention tips
- Keep the buttock crease clean and dry, especially after sweating.
- Avoid prolonged sitting — take short breaks if you sit for work.
- Remove excess hair in the area regularly.
- Maintain a healthy weight to reduce pressure on the area.
When to see a specialist
If you feel persistent pain near the tailbone, notice discharge or see a swelling that returns, do not wait for repeated flare-ups. An early consultation makes treatment simpler and reduces the chance of recurrence.