Systemic vasculitides diagnosed in children are mainly Henoch-Schönlein purpura (HSP), Kawasaki Disease and post-infectious vasculitis. The more severe forms of vasculitides are very rare during childhood and adolescence, with an estimated prevalence of about 1 for 100'000 children. We present the case of a 13 years old boy who presented with pain and swelling in the left ankle and with purpura on the adjacent skin. The laboratory showed roteinuria and microhematuria. The patient was diagnosed as HSP and received symptomatic treatment. Few days later, he developed bloody diarrhoea and abdominal pain. The abdominal ultrasound was normal, and he was treated with prednisone for a few days. Three weeks later, he presented diffused arthralgia, a painful and swollen calf, persistent abdominal pain, one
episode of hematemesis, and persistent hematuria and proteinuria. A Doppler ultrasound did not show thrombosis. He was then sent to the hospital for further investigations. The systematic anamnesis revealed asthenia and weight loss since a few months. He was also complaining about aphtous stomatitis, epistaxis, conjunctival hyperaemia, rash on the face and the elbows, headache and cervical pain. The laboratory showed systemic inflammation (ESR 47), normal blood count, normal liver, kidney and muscles values, elevated complement (C3 1,66g/l), normal antistreptolysin-O, negative
antinuclear antibodies. C-ANCA were positive with elevated antiproteinase3 (147kU/l). The diagnosis of Wegener's Granulomatosis was suspected on the clinical and laboratory findings. It was confirmed by a CT scan showing maxillary and ethmoidal mucosal thickening and multiple small opacities on both lungs, and by the histopathology of the kidney and the intestinal mucosa.
Our patient was treated with high dose steroids to induce the remission and azathioprine to allow steroid weaning. The evolution was favourable with complete inactivity of the disease and disappearance of the c-ANCA, even with low doses of steroids. The association of purpura, arthritis, proteinuria and abdominal pain is relatively common in childhood and suggests the diagnosis of HSP. Our case shows that children may develop other types of vasculitis which are less common and more severe. The physician should be
aware of the differential diagnosis with other vasculitides, when the presentation or follow-up are not classical. Early diagnosis of Wegener granulomatosis is essential for the prognosis and to avoid complications.