It appears rarely on the buttocks or groin or under the breasts. It is most common in females 13 to 15 years old, but it can occur in both sexes.
Nodules are firm, tender, and domed.
Nodules are 1cm to 3cm in diameter. Larger nodules soften in the center and become painful. When pressed, they feel like an overfilled inner tube. Nodules open and drain pus spontaneously. Nodules leave scars.