Three cases of cutaneous sarcoidosis: Search for bacterial agent by the 16S RNA gene analysis and treatment with antibiotics

Background: The aetiology of sarcoidosis remains controversial. An infectio us origin is often discussed, but only anti-inflammatory or immunosuppressi ve treatment is recommended. Objectives: To investigate the hypothesis of b acterial origin by treating cutaneous sarcoidosis with antibiotics. Methods : Patients with chronic cutaneous sarcoidosis, unresponsive to the usual tr eatment and not requiring systemic corticotherapy, were given combined anti biotherapy for 6 months. Search for bacterial DNA by amplification and sequ encing of the 16S ribosomal RNA gene in skin biopsies of lesions before and after antibiotherapy was done. Results: Three patients received a combined treatment with clarithromycin 1 g/day and ciprofloxacin 1 g/day. No clinic al changes occurred in 2 cases and transient worsening in 1. Amplification for bacterial DNA was positive in all skin biopsies. The sequencing of this DNA could not identify a unique bacterial species. Conclusion: No evident bacterial origin could be demonstrated; however, this approach should be ex tended to more patients. Copyright (C) 2000 S. Karger AG, Basel.