Boils
(Skin Abscesses)

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Boils facts

  • A boil, or skin abscess, is a collection of pus that forms in the skin.
  • Antibiotics alone can be inadequate in treating abscesses.
  • The primary treatments for boils include hot packs and draining ("lancing") the abscess but only when it is soft and ready to drain.
  • Boils themselves are not contagious, but the bacteria that cause boils are.
  • Most boils resolve on their own or with home remedies.
  • If you have a fever or long-term illness, such as cancer or diabetes, or are taking medications that suppress the immune system, you should contact your health care professional if you develop a boil (abscess).
  • There are a number of ways to reduce the likelihood of developing some forms of boils, but boils are not completely preventable.

What is a boil? What are the symptoms and signs of a boil?

A boil is a localized infection in the skin that begins as a reddened, tender area. Over time, the area becomes firm, hard, and more tender. Eventually, the center of the boil softens and becomes filled with infection-fighting white blood cells from the bloodstream to eradicate the infection. This collection of white blood cells, bacteria, and proteins is known as pus. Finally, the pus "forms a head," which can be surgically opened or spontaneously drain out through the surface of the skin. Pus enclosed within tissue is referred to as an abscess. A boil is also referred to as a skin abscess. Boils can occur anywhere on the body, including the trunk, extremities, buttocks, or other areas.

Picture of a Boil (Skin Abscess)
Picture: What does a boil look like?

There are several different types of boils:

  • Furuncle or carbuncle: This is an abscess in the skin usually caused by the bacterium Staphylococcus aureus. A furuncle can have one or more openings onto the skin and may be associated with a fever or chills. The term furuncle is used to refer to a typical boil that occurs within a hair follicle. The term carbuncle is typically used to represent a larger abscess that involves a group of hair follicles and involves a larger area than a furuncle. A carbuncle can form a hardened lump that can be felt in the skin. The condition of having chronic, recurring boils is referred to as furunculosis or carbunculosis.

Picture of a carbuncle
Picture of a carbuncle
  • Cystic acne: This is a type of abscess that is formed when oil ducts become clogged and infected. Cystic acne affects deeper skin tissue than the more superficial inflammation from common acne. Cystic acne is most common on the face and typically occurs in the teenage years.


  • Hidradenitis suppurativa: This is a condition in which there are multiple abscesses that form under the armpits and often in the groin area. These areas are a result of local inflammation of the sweat glands. This form of skin infection is difficult to treat with antibiotics alone and typically requires a surgical procedure to remove the involved sweat glands in order to stop the skin inflammation.


  • Pilonidal cyst: This is a unique kind of abscess that occurs in the crease of the buttocks. Pilonidal cysts often begin as tiny areas of infection in the base of the area of skin from which hair grows (the hair follicle). With irritation from direct pressure, over time the inflamed area enlarges to become a firm, painful, and tender nodule that makes it difficult to sit without discomfort. These frequently form after long trips that involve prolonged sitting.
Medically Reviewed by a Doctor on 6/28/2013

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Causes of Boils (Skin Abscesses)

Individuals who have ingrown hairs may experience a painful acne-like eruption after shaving. The upper skin layers may have some dilation of the small superficial blood vessels, which gives the skin a red or flushed appearance. Pustules and rare abscesses may form on the ingrown hair sites due to the infection with common skin bacteria, such as Staphylococcus and Pseudomonas.

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