An Infant With Acute FPIES: The New Guidelines

Stephanie A. Leonard, MD


August 09, 2017


FPIES is a non–immunoglobulin E (IgE)-mediated food allergy that classically presents with delayed, repetitive vomiting. In 2017, the first international consensus guidelines for the diagnosis and management of FPIES[1] were released, and the new recommendations will be reviewed here in the context of this case.

Data on the prevalence of FPIES are limited. One large-scale Israeli study[2] documented the cumulative incidence of cow's-milk FPIES as 0.34% over 2 years in an infant birth cohort. A more recent Australian population study reported the incidence of FPIES to be 15.4 per 100,000 per year in infants younger than 2 years.[3]

Age and nationality affect phenotype. For example, FPIES is predominantly diagnosed in infants but has also been reported in older children and adults, mostly related to seafood and egg. In most populations, cow's milk, soy, and grains are the most common FPIES triggers, and patients may have single or multiple triggers.

Cow's milk and soy FPIES often present earlier (< 6 months) than solid-food FPIES as a result of formula exposure. Concomitant cow's-milk/soy FPIES has been reported in up to 50% of US populations, but this has not been seen in Australia, Israel, or Italy. Concomitant rice/oat grain FPIES is common in both US and Australian populations. Fish FPIES is common in Italy and Spain, but not in other populations. Co-associated atopic conditions, such as eczema and IgE-mediated food allergy, are common in Australian and US populations, but not in Korea, Israel, or Italy. A family history of atopy may be present, and in the Australian population study, 7% of FPIES infants had siblings with a history of FPIES.[3]

Clinical features of acute FPIES include repetitive vomiting that typically occurs 1-4 hours (range, 30 minutes to 6 hours) after ingestion of the trigger food and may be projectile and bilious, and include dry heaving; altered activity levels ranging from decreased activity to lethargy; and pallor. Mild to moderate symptoms may be self-resolving, whereas moderate to severe symptoms may result in dehydration requiring IV fluids. Presentation may include diarrhea with mucus or blood that usually presents within 24 hours (most often within 5-10 hours). In severe reactions, hypotension, hypothermia, methemoglobinemia, metabolic acidosis, or abdominal distention may develop.

Laboratory findings may include neutrophilia that peaks at 6 hours and thrombocytosis. Stools may be positive for blood, leukocytes, eosinophils, or increased carbohydrate content. The presentation of FPIES does not include rash, angioedema, or respiratory symptoms, as sometimes seen in IgE-mediated food allergic reactions. Symptoms typically resolve within 24 hours (less than that expected for viral gastroenteritis), and patients are otherwise well in between exposures. Clinical diagnostic criteria that should be met for a diagnosis of FPIES include the major criterion and at least three minor criteria (Figure).[1]

Figure. Clinical diagnostic criteria for FPIES. ED = emergency department; IV = intravenous; FPIES = food protein-induced enterocolitis syndrome

The diagnosis of FPIES is clinical and primarily based on history. The condition is often underrecognized, and it is common for patients to be initially misdiagnosed.

The diagnosis of FPIES is clinical and primarily based on history. The condition is often underrecognized, and it is common for patients to be initially misdiagnosed, particularly because symptoms can look like gastroenteritis or sepsis. In addition, an infant may initially tolerate the trigger food, then develop symptoms after a period of avoidance and reintroduction.

If the history is not clear, then an oral food challenge may be used to confirm the diagnosis. This may be particularly helpful if there has only been one episode of vomiting, because viral gastroenteritis is common in infants.

Laboratory findings may help support a diagnosis and rule out other conditions, but they are not used alone to diagnose FPIES. Imaging, endoscopy, and stool tests are not recommended as a part of a suspected FPIES workup.

Skin-prick testing and specific IgE levels are typically negative in FPIES, which is consistent with a non–IgE-mediated condition. However, testing has been found to be positive in 2%-12% of patients upon FPIES diagnosis or follow-up, which could indicate a possible coexisting IgE-mediated food allergy. Studies have suggested a more protracted FPIES course if testing is positive.

Routine allergen testing is not recommended but may be considered if the patient has a comorbid medical condition that might increase their risk, such an IgE-mediated food allergy or atopic dermatitis.


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