Pediatric hypereosinophilic syndrome (HES) differs from adult HES

The idiopathic hypereosinophilic syndrome (HES) developed in a 15-year-old boy who presented with colitis, cough, rash, and hepatitis. Molecular analysis failed to demonstrate the Fip1-like1-Platelet Derived Growth Factor Receptor α chain (FIP1L1-PDGFRA) mutation described in adult patients with HES. There are significant clinical differences between the pediatric and adult presentations of HES.