Folliculitis, boils, and carbuncles are types of infections affecting one or more hair follicles. A hair follicle is the base or root of a hair. These infections can occur on any part of the skin with hair, but are most common in areas prone to rubbing and sweating, such as the back of the neck, face, armpits, waist, groin, and thighs.

A boil, also known as a furuncle, starts as a painful infection of a single hair follicle. Boils can grow larger than a golf ball, often appearing on the buttocks, face, neck, armpits, and groin. A carbuncle is a deeper skin infection involving a group of infected hair follicles in one area.

The most common cause of these infections is the bacteria Staphylococcus aureus, which normally lives on the skin, particularly in areas like the nose, mouth, genitals, and rectum. Infection occurs when the bacteria enter the skin through a scrape, irritation, or injury.

Folliculitis is the inflammation of hair follicles, which can be caused by bacteria, fungus, or irritants. It often results in tender, swollen areas around the hair follicles, especially on the neck, breasts, buttocks, and face. Boils are painful, pus-filled lesions, typically found in the waist area, groin, or buttocks.

Hidradenitis suppurativa (HS) is a chronic skin disease causing deep, painful boils or abscesses. It occurs when the deep roots of hair follicles get blocked, commonly in areas where skin rubs together, like the armpits and groin.

Severe folliculitis may rarely lead to hair loss or scarring. Treatment and management of these conditions vary based on the severity and underlying cause.

For more detailed information on these conditions, visit University of Rochester Medical Center, Harvard Health, and URMC Health Encyclopedia.