Food Protein-Induced Enterocolitis Syndrome (FPIES) is a severe systemic response to food protein that typically occurs 1 to 4 hours after the ingestion of the causative food and frequently develops in the first few years of life. In the severe form, patients will vomit until dehydration and until a shock-like state, which occurs in 15% of patients. FPIES occurs primarily in young infants, but can exist in older children and adults.
In the severe form, symptoms include vomiting, diarrhea, and acidosis. There is a variant of FPIES and it manifests as chronic vomiting, diarrhea, and failure to thrive. Upon re-exposure to the offending food after a period of elimination, a subacute syndrome can present with repetitive emesis and dehydration.
The exact mechanism is unclear, but it is hypothesized to be a T cell driven disorder. Milk and soy protein are the most common trigger foods, but other foods have been reported including rice, oat, chicken, peanut, potato, fish, and egg. A similar condition also has been reported in adults, most often related to crustacean shellfish ingestion. There are also cases of FPIES being transmitted through foods in breast milk in rare occasions.
Complete avoidance of the triggering factors is the best way to prevent occurrence of the symptoms of FPIES.
Laboratory studies during the acute episode shows an elevated white blood cell count with a left shift and elevated platelet count and methemoglobinemia. In one study, atopy patch tests was found to be helpful. FPIES is usually diagnosed clinically based on medical history and examination. There are no simple lab tests to identify triggers; food-specific IgE tests and skin prick tests are typically negative.
Studies have found 90% of the children outgrew it by 3 years of age.
Strict avoidance of the offending food is the required treatment.