A cluster of interconnected boils (pus-filled, painful, inflamed hair roots). Carbuncles are often caused by infection with the bacterium staphylococcus aureus. The buttocks and back of the neck are the most common areas affected. The swellings mainly affect people with a reduced immunity, especially those with diabetes mellitus.
Treatment is often with an antibiotic drug. In addition to this, the application of a hot compress can encourage the pus-filled boils to burst, which will in turn relive the pain. Sometimes incision and drainage (together with the removal of the carbuncle) can be necessary if the carbuncle is persistent, and healing and drainage have not come about spontaneously.