False positive antineutrophil cytoplasmic antibody in a patient with infective endocarditis

We report a gentleman suffering from purpuric skin rash mimicking vasculitis associated with impaired renal function. He was found to have positive cytoplasmic antineutrophil cytoplasmic antibodies (c-ANCA) in the serum, but the test for anti-proteinase 3 antibodies (PR3-ANCA) was negative. Blood culture and echocardiogram confirmed the diagnosis of Streptococcal Oralis infective endocarditis. The renal biopsy did not show any features of vasculitis or crescentic glomerulonephritis. His skin rash subsided and renal function normalized after treatment of the infective endocarditis with appropriate antibiotics. Therefore, we conclude that for those patients presenting with features of vasculitis and a positive ANCA test, other causes, such as infective endocarditis, should be considered.