The authors report on the case of a 10-year-old girl who presented with a vasculitic process primarily involving the skin, joints and kidneys, which was initially presumed to be a variant of Henoch-Schonlein purpura. When the disease process behaved in a more aggressive way than expected, with the rapid onset of acute renal failure, further investigation revealed the underlying diagnosis to be that of Wegener's granulomatosis.