Cat scratch disease (bartonellosis) mimicking an SLE flare

Only recently Bartonella species have been recognized as important human pathogens. Cat scratch disease (CSD), caused by infection with Bartonella henselae, shows a steady increase in the number of cases throughout the world. We report a case of an 18-year-old woman with systemic lupus erythematosus (SLE) who presented with ongoing fever, arthralgias and loss of weight which did not respond to increasing doses of corticosteroids. After exclusion of common infections a photograph of her cat in combination with scratch marks on her arms finally led to the suspicion of CSD. This tentative diagnosis was confirmed serologically. Under clarithromycin treatment the patient rapidly responded and her temperature dropped within 2 days.