Furuncle (boil)

Staph. aureus is also the main cause of acute bacterial folliculitis, which is known as a furuncle (boil) when deep and involving the entire follicle and its surrounding tissue. The axilla is a common location. A furuncle is a tender erythematous nodule, and becomes larger and more painful as a walled-off collection of pus develops. It is more common in adolescents, or those with diabetes, obesity or immunodeficiency. There are not usually any systemic symptoms.
Treatment is not necessary for a single simple furuncle, however fluctuant lesions require incision and drainage. Systemic antibiotics are recommended for large, recurrent or persistent lesions, or if there is surrounding cellulitis.