Bacteriology of inflamed and uninflamed epidermal inclusion cysts.

OBJECTIVE To determine whether inflamed and uninflamed epidermoid cysts differ in the number and/or type of bacteria inhabiting them. DESIGN A controlled study. We obtained aerobic and anaerobic bacterial culture specimens from 25 inflamed and 25 uninflamed epidermoid cysts. SETTING A university medical center. PATIENTS Nonimmunocompromised adults without recent systemic use of antibiotics. RESULTS The 2 groups did not differ significantly with respect to number of bacterial isolates, "no growth" cultures, and aerobic, anaerobic, or potential pathogens cultured. CONCLUSIONS The microbiological milieu of inflamed epidermoid cysts is similar to that of uninflamed cysts. Possible mechanisms for inflammation are discussed.