Carbuncle Information

A carbuncle is a collection of multiple infected hair follicles. It is an abscess, just like a furuncle is an abscess but a carbuncle is a much more serious infection. Whereas a furuncle is an infection of a hair follicle and the surrounding tissue, a carbuncle is actually several furuncles that are densely packed together.

Carbuncle Appearance

A carbuncle usually extends into the deeper layers of the skin -- the subcutaneous fat.

It forms into a broad, red, hot, painful nodule that often drains pus through multiple openings of the skin. Someone who has a carbuncle likely will feel sick and have a fever and fatigue. Carbuncles tend to occur in areas with thicker skin like the nape of the neck, the back, or the thighs.

How Carbuncles are Diagnosed

Carbuncles are diagnosed based on their typical appearance, but sometimes they can be confused with a ruptured epidermoid cyst. There aren't any tests that are performed to decide if an infection is a carbuncle, but often the pus inside the carbuncle is tested with a gram stainĀ or bacterial culture to determine if the bacteria causing the infection is a typical Staphylococcus aureus or one that is resistant to the usual penicillin-type antibiotics.

Treatment of Carbuncles

Because carbuncles usually contain a significant amount of pus, they are usually first treated with a procedure called incision and drainage (I&D) draining the pus and allowing the infection to heal from the inside out.

Carbuncles are typically caused by the bacteria, Staphylococcus aureus. The usual medications used to treat Staph infections include the antibiotics dicloxacillin or cephalexin. Unfortunately, there is a new strain of Staph bacteria that is resistant to these antibiotics.

Carbuncles Caused by Methicillin-Resistant Staphylococcus Aureus (MRSA)

In the past several years, there has been a sharp increase in the incidence of infections caused by a special strain of S.

aureus that is resistant to the normal penicillin-based treatment. Until recently, MRSA was an uncommon bacterial strain that occurred in nursing homes and other long-term care facilities. But with the overuse of antibiotics for conditions that don't require antibiotics, MRSA infections are common in certain regions of the United States.

These infections often occur spontaneously in the groin, buttock, and upper thigh region. Currently, there are antibiotics that do treat this resistant strain. The antibiotic of choice for MRSA infections that were not acquired from a hospital or long-term care facility is trimethoprim-sulfamethoxazole (Septra or Bactrim). The next option is clindamycin, especially for people who are allergic to sulfa.


Habif, Thomas. "Bacterial Infections." Clinical Dermatology, 4th Edition. Ed. Thomas Habif, MD. New York: Mosby, 2004. 236-62.

Halpern, Analisa and Warren Heymann. "Bacterial Diseases." Dermatology. 2nd. Ed. Jean Bolognia. New York: Mosby, 2008: 1075-84.

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