Alternative names
Skin infection - staphylococcal; Infection - skin - staph; Staph skin infection; Carbuncles

A carbuncle is a local, but deep, staphylococcal skin infection.

Causes, incidence, and risk factors
A carbuncle consists of several furuncles that develop close together. They expand and join together to form a larger mass (aggregation of cells) with multiple drainage points. This mass may be deeper beneath the skin surface than simple furuncles. They develop slowly, and may be so deep that they do not drain on their own. Carbuncles may develop anywhere, but they are most common on the back and the nape of the neck. Carbuncles are less common than boils. Men are more prone to carbuncles than women.

Staph skin infections are contagious. They may spread to other areas of the body, and may spread to other people. It is not uncommon for several family members to be affected at the same time. Poor hygiene, run-down physical condition, friction from clothing or shaving, and similar factors may make them more likely. Diabetics and people with suppressed immune systems are more prone to development of staph skin infections, as are people with dermatitis (skin inflammations). Often, however, no direct cause is found for furunculosis or carbunculosis.


  • skin lesions       o papule or nodule       o usually pea-sized, may occasionally be as large as a golf ball       o swollen       o pink or red       o may grow rapidly       o may develop white or yellow centers (pustules)       o may weep, ooze, or crust       o maybe located with hair follicles       o tender, mildly to moderately painful       o may be single or multiple       o may run together (coalesce) or spread to other skin areas       o pain increases as pus and dead tissue fills the area       o pain decreases as the area drains  
  • skin redness or inflammation around the boil  
  • fever (occasionally)  
  • fatigue (occasionally)  
  • general discomfort, uneasiness, or ill feeling (occasionally)

Itching of the skin may occur before the skin lesions develop.

Signs and tests
Diagnosis is primarily based on the appearance of the skin. A skin biopsy and bacterial culture of the lesion may help to make the diagnosis or determine the exact type of bacteria involved.

Carbuncles usually must drain before they will heal. This most often occurs in less than 2 weeks. Carbuncles that persist longer than 2 weeks, recur, are located on the spine or the middle of the face, or that are accompanied by fever or other symptoms require treatment by a health care provider because of the risk of complications from the spread of infection.

Antibacterial soaps, topical (applied to a localized area of the skin) antibiotics, and systemic antibiotics may help to control infection. Warm moist compresses encourage carbuncles to drain, which speeds healing. Gently soak the area with a warm, moist cloth several times each day. Never squeeze a boil or attempt to lance it at home because this can spread the infection and make it worse.

Deep or large lesions may need to be drained surgically by the health care provider.

Meticulous hygiene is vital to prevent the spread of infection. Draining lesions should be cleaned frequently. The hands should be washed thoroughly after touching a boil. Do not re-use or share washcloths or towels. Clothing, washcloths, towels, and sheets or other items that contact infected areas should be washed in very hot (preferably boiling) water. Dressings should be changed frequently and discarded in a manner that contains the drainage, such as by placing them in a bag that can be closed tightly before discarding.

Expectations (prognosis)
Carbunculosis may heal spontaneously and usually responds well to treatment. It often recurs for months or years following an initial infection.


  • spread of infection to other skin surfaces  
  • abscess formation  
  • sepsis (general internal infection)  
  • abscess of kidneys or other internal organs  
  • osteomyelitis  
  • endocarditis  
  • brain infection  
  • brain abscess  
  • spinal cord infection  
  • Spinal cord abscess  
  • permanent scarring of the skin

Calling your health care provider
Call for an appointment with your health care provider if carbuncles develop and do not heal with home treatment within 2 weeks.

Call for an appointment with your health care provider if carbunculosis recurs or is located on the face or spine.

Call for an appointment with your health care provider if carbuncles are accompanied by fever, red streaks extending from the carbuncle, large fluid collections around the carbuncle, worsening pain, or other symptoms.

Good general health and hygiene may help prevent some staph skin infections. These infections are contagious, so care must be taken to avoid contamination of other skin areas or other people.

Johns Hopkins patient information

Last revised: December 3, 2012
by Levon Ter-Markosyan, D.M.D.

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