Question: A 5-year old Caucasian boy presented with sudden onset of diffuse purpuric and petechial skin lesions without fever at the pediatric department. The following days he developed diffuse abdominal pain with bloody stools (4-6 times a day). He also complained of scrotal pain and joint pain (knee, ankles). His previous medical history was unrevealing. Family history was negative for autoimmune or gastrointestinal diseases. He had not taken medication besides paracetamol. Clinical examination revealed an alert but tachycardic boy with a blood pressure of 130/90 mm Hg.