Non–IgE-mediated severe gastrointestinal food hypersensitivity, typically presents in early infancy with repeated vomiting, diarrhoea, dehydration, and lethargy.  The severity is really what makes it worthy of a distinct name, debatable if it is actually distinct from other non-IgE mediated food allergy. But a few unusual features.

The most common offending foods are cow’s milk and soy in young infants; in older infants, there are a range of food triggers including some foods usually not considered allergenic eg rice, oat, chicken, sweet potato!  Egg surprisingly a very unusual cause!  Cases in breastfed infants have been reported.

Acute symptoms occur 1 to 5 hours after ingesting the offending food.  Chronic onset seen within 1-4 weeks of food introduction, similar symptoms but also failure to thrive.  Chronic usually turns into acute on challenge!

Diagnosis is based, predictably for a non-IgE condition, on clinical history and food challenges.  Leucocytosis and methaemoglobinaemia are associated but low specificity/sensitivity.  Oral food challenge where FPIES suspected would be done with IV access, and divided portions of 0.15-0.3g/kg over 1 hour.

FPIES is usually outgrown by school age. Management is simply avoidance of the offending food, natural history appears to vary for different foods which makes it difficult to judge reintroduction.

Annals of Allergy, Asthma & Immunology, Volume 107, Issue 2, August 2011, Pages 95–101