Ehrlichiosis associated vasculitis.

Objective: To test the hypothesis that some cases of primary vasculitis are caused by ehrlichiosis.

Design: A retrospective case study and serological analysis of stored sera.

Setting: University hospital.

Subjects: Fifty-five patients discharged with any type of vasculitis over a 6-year period.

Main Outcome Measures: Serology for human monocytic ehrlichiosis, and the human granulocytic ehrlichiosis agent, and polymerase chain reaction (PCR) analysis of biopsy specimens.

Results: Three patients (5.5%) had titres of 1 : 128 or higher against E. chaffeensis; none was positive for the human granulocytic ehrlichiosis agent. Skin biopsies of these patients showed lesions compatible with polyarteritis nodosa, allergic purpura and unspecified vasculitis. PCR analysis of the biopsies was unrevealing.

Conclusions: Infection with human monocytic ehrlichiosis may underlie some forms of vasculitis. If confirmed, these findings may help identify patients with vasculitis who would benefit from antibiotic treatment.