Boils tend to occur on parts of the body that have hair or sweat glands and are exposed to friction, typically on the face, neck, armpits or buttocks. There are a variety of different types of boils:
Furuncle or Carbuncle. These abscesses are caused by the Staphylococcus aureus bacterium. A furuncle is an individual boil; carbuncles are deep clusters of boils that most often form on the back of the neck, shoulders or thighs.
Pilonidal Cyst. An infected hair follicle around the buttocks area caused by long periods of sitting. Pilonidal cysts almost always require medical treatment.
Hidradenitis Suppurativa. These are multiple abscesses that form from blocked sweat glands in the armpits or groin areas.
Cystic Acne. These boils are situated more deeply into skin tissue than the more superficial forms of acne. It typically occurs among teenagers.