Patients often get worse shortly after therapy, with further extension of the cellulitis, higher fever, greater toxicity, and increased white blood cell counts, presumably because rapid killing of the organisms releases potent enzymes, such as streptokinase and hyaluronidase, that cause many of the clinical features. In patients with leg cellulitis, treatment of tinea pedis is useful in preventing further episodes, which are likely to cause permanent lymphatic damage and can lead to lymphedema and further risk of infection. Other measures to diminish the frequency of future attacks include control of edema by diuretics or mechanical means, such as elastic stockings, and, for those with frequent episodes, prophylactic antibiotics. With involvement of several adjacent follicles, a mass called a carbuncle may occur, with pus discharging from multiple follicular orifices. This infection typically develops on the back of the neck and appears more commonly in patients with diabetes than in the general population.
Moist heat is usually adequate for small furuncles, which ordinarily drain spontaneously.
Incision and drainage are appropriate for large or multiple furuncles and for all carbuncles. Systemic antibiotics are unnecessary unless there is fever or substantial surrounding cellulitis. Some patients have recurrent episodes of furunculosis. From this site or occasionally from the perineum or axilla, organisms can spread and enter the skin, presumably through minor, usually inapparent, trauma. Successful prevention of recurrent infection requires eradication of these bacteria from their site of residence, but most systemic antibiotics do not achieve adequate levels of drug in the anterior nares.