Characteristic cutaneous lesions in patients with brucellosis

Among 436 cases of brucellosis included in a 12-year prospective protocol, we identified 27 patients (6%) with cutaneous lesions (13 men and 14 women; mean age, 35.1 +/- 16.5 years). Twenty-one patients had positive blood cultures for Brucella melitensis. A disseminated violet-erythematous, papulonodular eruption (20 cases) and erythema nodosum-like lesions (three cases) were the most frequent eruptions observed, appearing during the initial episode of the disease or in relapse. Histologic findings were a dermal inflammatory infiltrate of lymphocytes and histiocytes in a perivascular and periadnexal arrangement, with a focally granulomatous appearance, and occasional extension to subcutaneous fat. Skin cultures were positive for B melitensis in two of four cases. Our results suggest that there are characteristic clinical and histologic cutaneous findings in patients with brucellosis and that hematogenous spread of the microorganism can be the most important pathogenic mechanism of these lesions.