Abstract
This study aimed to investigate the clinical characteristics of severe food protein-induced enterocolitis syndrome (FPIES) in patients with Down syndrome. We report the cases of three infants with Down syndrome who were diagnosed with FPIES. All patients presented with hypovolemic shock, metabolic acidosis, and acute kidney injury after introducing a milk-based formula. They required aggressive fluid resuscitation and alternative nutrition. All three patients survived without any complications after the treatment. FPIES may cause hypovolemic shock in infants with Down syndrome and these patients need prompt fluid resuscitation.