The Role of Chlamydia pneumoniae in the Etiology of Acne Rosacea: Response to the Use of Oral Azithromycin

Acne rosacea is a chronic skin disorder that requires long-term therapy. Oral azithromycin has been used successfully to treat acne vulgaris, an observation that suggested an infectious agent may play an active role in the etiology of this disorder. Ten adults (not previously reported) with acne rosacea were selected to be treated with oral azithromycin. Nine of the 10 subjects received 250 mg 3 times weekly for periods ranging from 5 to 19 weeks, at which time follow-up examinations were performed on 8 of the 9 treated subjects; 1 subject was lost to follow-up. Prior to therapy, C pneumoniae antigen was detected in malar biopsy specimens in 4 of 10 subjects by immunoperoxidase technique (using monoclonal antibody to C pneumoniae). Serum antibodies against C pneumoniae were detected in 8 of 10 intent-to-treat subjects. Using polymerase chain reaction, C pneumoniae was not detected in peripheral blood mononuclear cells. The inflammatory response in tissues was characterized by a widespread infiltration of polymorphonuclear neutrophil cells, lymphocytes, and plasma cells, which support the clinical diagnosis of acne rosacea. Nine of 10 subjects treated with azithromycin showed moderate to marked improvement of their acne rosacea. No adverse reactions to azithromycin occurred, and the drug appeared to be safe and effective. These preliminary data suggest the need for further investigation with clinical trials to study long-term tolerability and efficacy and also strongly implicate C pneumoniae in the pathogenesis of acne rosacea.