Pilonidal cysts typically develop above the cleft of the buttocks. These swollen lumps contain hair or other debris. They occur when small holes in the skin, known as pilonidal sinuses, become ...

Also known as a pilonidal cyst, the condition forms when a sac of tissue fills with air or fluid in the crease of your buttocks. Pilonidal cyst, doctors say, is mostly caused by a skin infection.

A pilonidal sinus is a small tunnel that develops at the top of the crease in the buttocks. Trapped hair around the buttocks crease can lead to an abscess, and a pilonidal sinus may develop as a ...

A pilonidal sinus is a small infected tract or a network of interlinking tracts under the skin between the buttocks. The exact cause is unknown but it may be from loose hairs pushing into the skin, ...