Food protein-induced enterocolitis syndrome (FPIES) has recently been reported to occur from orange juice, a previously unrecognized cause. FPIES mimics food allergy, but it is not mediated by IgE (Immunoglobulin E), the usual allergic mechanism. It is an acute inflammation of the GI tract, caused by a food protein that leads to nausea, vomiting and diarrhea. Frequently, affected children become dehydrated and require IV fluids. The condition is often mistaken for a GI flu until the causal association with a food protein is recognized. The most common cause for FPIES is cow milk. The diarrhea seen with cow milk ingestion is often bloody and, hence, quite startling to unsuspecting parents of infants who develop FPIES.
Other well-recognized causes: rice and soy protein. The newly described cause is fruits (including apple, pear and banana) and most recently, orange juice. Unlike with food allergy, children with FPIES have no rash, angioedema or respiratory symptoms. Also, the reaction (unlike with food allergy which tends to be immediate) is generally delayed two-to-four hours after ingestion of the trigger food. Because FPIES is not a classic allergic condition, it cannot be diagnosed by allergy testing. The best method for diagnosis is recognizing the suspected food as an antecedent to the symptoms. Also, oral food challenge tests can be conducted to confirm the diagnosis.