What is Pilonidal Sinus?
Pilonidal sinus is a small hole or tunnel in the skin which is filled with pus. This forms a cyst or an abscess in the cleft at the top of buttocks. The pilonidal sinus usually contains hair, dirt and debris. It can be extremely painful and can become infected quickly.
If it gets infected, it may ooze pus or blood and emit a foul odour.