Most carbuncles are caused by the bacteria Staphylococcus aureus. The infection is contagious. This means it can spread to other areas of the body or other people.
A carbuncle is made up of several skin boils (furuncles). The infected mass is filled with fluid, pus, and dead tissue. Fluid may drain out of the carbuncle, but sometimes the mass is so deep that it cannot drain on its own.
Carbuncles can develop anywhere. But they are most common on the back and the nape of the neck. Men get carbuncles more often than women.
Because the bacteria that causes the condition is contagious, family members may develop carbuncles at the same time. Often, the cause of a carbuncle cannot be determined.
You are more likely to get a carbuncle if you have:
Friction from clothing or shaving
Poor overall health
Persons with diabetes, dermatitis, and a weakened immune system are more likely to develop staph infections that can cause carbuncles.
A carbuncle is a swollen lump or mass under the skin. It may be the size of a pea or as large as a golf ball. The carbuncle may be red and irritated and might hurt when you touch it.
The health care provider will look at your skin. The diagnosis is based on what the skin looks like. A sample of the pus may be sent to a lab to determine the bacteria causing the infection (bacterial culture). The test result helps your provider determine the appropriate treatment.
Carbuncles usually must drain before they will heal. This most often occurs on its own in less than 2 weeks.
Placing a warm moist cloth on the carbuncle helps it to drain, which speeds healing. Apply a clean, warm moist cloth several times each day. Never squeeze a boil or try to cut it open at home, because this can spread the infection and make it worse.
You need to seek treatment if the carbuncle:
Lasts longer than 2 weeks
Is located on the spine or the middle of the face
Occurs with a fever or other systemic symptoms
Treatment helps reduce complications related to an infection.Your provider may prescribe:
Antibiotics applied to the skin or taken by mouth
Deep or large lesions may need to be drained by your provider.
Proper hygiene is very important to prevent the spread of infection.
Wash your hands thoroughly with soap and warm water after touching a carbuncle.
Do not re-use or share washcloths or towels. This can cause the infection to spread.
Clothing, washcloths, towels, and sheets or other items that contact infected areas should be washed in very hot (preferably boiling) water.
Bandages should be changed often and thrown away in a bag that can be tightly closed.
Carbuncles may heal on their own. Others usually respond well to treatment. A carbuncle can return again and again for months or years following the first infection.
Untreated, carbuncles may lead to any of the following:
Pallin DJ, Nassisi D. Skin and soft tissue infections. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 8th ed. Philadelphia, PA: Elsevier Mosby; 2014:chap 137.
Kevin Berman, MD, PhD, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.