Educational clinical case series for pediatric allergy and immunology: allergic proctocolitis, food protein-induced enterocolitis syndrome and allergic eosinophilic gastroenteritis with protein-losing gastroenteropathy as manifestations of non-IgE-mediated cow's milk allergy.

Cow's milk protein allergy is the most common food allergy in infants and young children. It is estimated that up to 50% of pediatric cow's milk allergy is non-IgE-mediated. Allergic proctocolitis is a benign disorder manifesting with blood-streaked stools in otherwise healthy-appearing infants who are breast- or formula-fed. Symptoms resolve within 48-72 h following elimination of dietary cow's milk protein. Most infants tolerate cow's milk by their first birthday. Food protein-induced enterocolitis syndrome presents in young formula-fed infants with chronic emesis, diarrhea, and failure to thrive. Reintroduction of cow's milk protein following a period of avoidance results in profuse, repetitive emesis within 2-3 h following ingestion; 20% of acute exposures may be associated with hypovolemic shock. Treatment of acute reactions is with vigorous hydration. Most children become tolerant with age; attempts of re-introduction of milk must be done under physician supervision and with secure i.v. access. Allergic eosinophilic gastroenteritis affects infants as well as older children and adolescents. Abdominal pain, emesis, diarrhea, failure to thrive, or weight loss are the most common symptoms. A subset of patients may develop protein-losing enteropathy. Fifty percent of affected children are atopic and have evidence of food-specific IgE antibody but skin prick tests and serum food-IgE levels correlate with response to elimination diet poorly. Elemental diet based on the amino-acid formula leads to resolutions of gastrointestinal eosinophilic inflammation typically within 6 wk.