Onset of cutaneous vasculitis and exacerbation of IgA nephropathy after Bartonella henselae infection.

Bartonella henselae is the aetiological agent of cat-scratch disease. Recently, there have been reports of other conditions associated with this bacterium, including leucocytoclastic vasculitis, thrombocytopenic purpura, maculopapular and urticarial eruptions, granuloma annulare, erythema nodosum, erythema marginatum and erythema annulare. We report the first case, to our knowledge, of the simultaneous occurrence of cutaneous vasculitis and nephrotic syndrome in a 65-year-old woman with IgA nephropathy after a B. henselae infection transmitted by a cat scratch. The aetiopathogenetic role of B. henselae was hypothesized on the basis of the serological demonstration of acute B. henselae infection, the immunofluorescence findings, and the prompt resolution after azithromycin treatment. Patients reporting cat scratches or bites should undergo accurate clinical examination, routine laboratory examinations, urinalysis and clinical surveillance.