FPIES: The 'Other' Food Allergy

Anna Nowak-Wegrzyn, MD


April 03, 2013

FPIES Diagnosis

Diagnosis of FPIES is not straightforward because the child will not have food-specific IgE antibodies to aid in the diagnosis. If a small child or infant presents with repeated episodes of severe emesis, with or without hypotension upon ingestion of the food, and is well when the implicated food is eliminated from the diet, the diagnosis of FPIES can be established on clinical grounds and an oral food challenge (OFC) is not necessary. However, OFCs are recommended if the child has chronic symptoms despite dietary restrictions and is not thriving in order to both confirm the diagnosis and identify the offending foods. OFCs are also necessary during follow-up to determine when a child has "outgrown FPIES."

An OFC for FPIES is considered a high-risk procedure because of the potential for hypotension. It is usually performed with secure IV access in place prior to the beginning of the challenge. During a food challenge, a serving of food is fed over 45-60 minutes, usually in 3 equal portions, followed by a minimum of 4 hours of observation prior to discharge. A complete blood count is obtained at baseline, before the start of the challenge, and again 4-6 hours later only if symptoms develop, because an elevation in neutrophil count of > 3500/mL is one of the diagnostic criteria for a positive challenge. It should also be repeated prior to discharge if symptoms are absent.