Food protein–induced enterocolitis syndrome (FPIES)

Non–IgE-mediated severe gastrointestinal food hypersensitivity, typically presents in early infancy with repeated vomiting, dehydration, lethargy, metabolic acidosis (even mimicking sepsis).  Watery diarrhoea (sometimes with blood and/or mucus) can develop in some cases. 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.

Probably underdiagnosed.

A few unusual features cf type 1 allergy.

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.  Lasts up to 24 hours. Not always consistent, which might suggest co-factors important.

Chronic FPIES less well characterised – Japan, Korea more? Usually young babies fed formula. Chronic vomiting, diarrhoea, faltering growth, hypoalbuminaemia. 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.

No consensus on when to rechallenge. Hospital challenge, obviously. 12 months? 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.

Pediatric Allergy & Immunology. 25(7):622-9, 2014 Nov. UI: 24853552

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