It often starts as a sore spot you assume is a zit, ingrown hair, or minor irritation. Then it gets worse. Sitting becomes uncomfortable. Pressure builds. Sometimes there’s swelling, drainage, or even ...

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.