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 h uman granulocytic ehrlichiosis agent, and polymerase chain reaction (PCR) a nalysis of biopsy specimens. Results. Three patients (5.5%) had titres of 1 : 128 or higher against E. c haffeensis; none was positive for the human granulocytic ehrlichiosis agent . Skin biopsies of these patients showed lesions compatible with polyarteri tis nodosa, allergic purpura and unspecified vasculitis. PCR analysis of th e biopsies was unrevealing. Conclusions. Infection with human monocytic ehrlichiosis may underlie some forms of vasculitis. If confirmed, these findings may help identify patient s with vasculitis who would benefit from antibiotic treatment.