Pilonidal sinus—also called a pilonidal cyst—is a skin infection that occurs in or around the crease of your buttocks. This condition happens when hair, skin cells, and dirt clog a hair follicle, ...

A 27-year-old man will have a scar on his face for the rest of his life, after what he thought was a pimple turned out to be an infected cyst. In late 2024, Kai Davidson noticed a small lump on the ...