Carbuncles

Alternative names

Skin infection - staphylococcal; Infection - skin - staph; Staph skin infection; Carbunculosis

Definition

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.

Symptoms

• 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.

Treatment