FPIES

Today's Food Allergy expert, Dr. Anna Nowak-Wegrzyn, discusses a different manifestation of food allergies called F.P.I.E.S.

Kosher with Food Allergies Interview Series

Interview #6 Food Protein-Induced Enterocolitis Syndrome, Dr. Anna Nowak-Wegrzyn

What is FPIES?

Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE-mediated food allergy manifesting with gastrointestinal symptoms in young infants with an onset in the first year of life. It is presumed that in FPIES, T lymphocytes in the gut recognize foods and elaborate many chemicals that lead to FPIES symptoms. Rarely, FPIES may start at an older age, to foods such as fish and shellfish, particularly mollusks (scallop).

How is FPIES different from food allergies?

There are several critical differences:
1. FPIES symptoms are usually delayed [onset within 1-3 hours] compared to classic, anaphylactic
food allergies [onset within minutes to 1 hour], following food ingestion.
2. There are never skin or breathing symptoms in acute [sudden onset] FPIES.
3. Allergy tests, prick skin tests and serum food-specific IgE levels are negative.
4. Management of acute FPIES episodes relies on rehydration [usually via a line inserted into
a vein in an arm, in mild cases, orally] and a single dose of a steroid given through the vein.
Epinephrine, antihistamines, and inhaled asthma medications are not helpful.
5. Unlike classic food allergies, rice and oat are among the most common foods causing FPIES,
in addition to cow milk, soybean, fruits and vegetables, and fish. In contrast, FPIES to wheat
and egg is uncommon, unlike in classic food allergy.

What are symptoms of FPIES

When food is eaten infrequently, FPIES presents acutely as severe, projectile and repeated vomiting [up to 15-20 episodes], lethargy, and pale/ashen grey appearance within 1-3 hours after food ingestion. Child may feel cool to touch and have low core body temperature. In some children, especially with severe vomiting, diarrhea with blood and mucous may follow, starting within 2-5 hours. One in 5 children become hypotensive with low blood pressure and require admission to the hospital for emergency treatment. White blood count is usually elevated with left shift suggesting infection; frequently children undergo extensive testing to rule out sepsis [blood infection] and are treated with antibiotics. Because FPIES lacks classic allergic symptoms such as hives, itching, swelling, cough or wheezing, food allergy is not obvious and children undergo many diagnostic tests to exclude metabolic disorders, neurological or cardiac defects and gastrointestinal obstruction. Some children experience several acute episodes before food allergy is diagnosed, with the most common diagnosis of exclusion being viral gastroenteritis. Even when food allergy is suspected and allergy tests are done, negative results of skin prick test and serum food-specific IgE may lead to confusion. When food is eaten on a regular basis, as in the young infants fed with cow milk or soy-based infant formula, symptoms are chronic and include intermittent vomiting without clear association with food ingestion, bloody diarrhea, poor weight gain or weight loss, colic, and irritability. Laboratory tests show elevated white blood count, anemia, low albumin and protein. Children ultimately get very sick and are admitted to the hospital, intravenous fluids and antibiotics are given for presumed infection. Feedings are stopped for few days with resolution of symptoms on intravenous fluids. When feedings with cow milk or soy-based infant formula are re-started, symptoms of acute FPIES develop in 1-3 hours following feeding. So there is a transition between chronic and acute symptoms, depending on frequency and regularity of food intake.

How is FPIES treated?

As with all food allergies, strict avoidance of food in the diet is the mainstay of long-term therapy. Unlike in classic food allergy to cow milk and egg, where the majority (up to 75%) tolerate milk and egg in the baked products, children with cow milk and egg FPIES appear to react to baked forms of these foods. Most breastfed infants remain well and asymptomatic while the mother ingests foods that cause FPIES upon direct feeding, therefore avoidance of these foods in mother’s diet is not necessary. Very rarely symptoms develop to milk proteins in mother’s milk; if this happens mother’s diet has to be modified. If a child is formula-fed, hypoallergenic formulas are usually well tolerated; about 15% may need amino acid based formula. Since FPIES is not familiar to the majority of the Emergency Department physicians, we provide families with an emergency letter that describes symptoms and treatments of FPIES to avoid mismanagement. Epipnephrine autoinjectors and oral antihistamines are not routinely prescribed for patients with FPIES. Acute FPIES is an emergency and families are instructed to call 911 or go to the Emergency Department for treatment. In mild cases, oral rehydration may be successful. Most reactions may require intravenous fluids for speedy recovery. In more severe reactions, a single dose of a steroid is usually given via an intravenous line. Epinephrine, antihistamines, and inhaled asthma medications are not helpful for symptoms of vomiting or diarrhea. However, if blood pressure is very low, epinephrine may be used to bring the blood pressure up in the emergency setting.

Can FPIES be outgrown?

Of course, most children outgrow FPIES. The timing of outgrowing seems to depend on the severity of FPIES. In milder cases, the majority, over 90% of children outgrow FPIES by age 3 years. In more severe FPIES to multiple foods, about one third of children outgrow FPIES by age 3.

What type of Specialist can diagnose FPIES?

Given the atypical, mostly gastrointestinal symptoms, many infants and children with FPIES are being referred to pediatric gastroenterologists. However, the allergists are most familiar with FPIES manifestations and are most likely to make a correct diagnosis without a delay and to provide a diagnostic oral food challenge, if needed. There seems to be a lot of confusion about FPIES, with many children with chronic diarrhea being labeled as FPIES. Many of these children with presumed FPIES remain symptomatic despite a growing list of eliminated foods and are not likely to have FPIES. In such cases, oral food challenges are necessary to confirm or exclude FPIES; absence of acute FPIES symptoms during food challenge excludes FPIES and alternative diagnosis have to be investigated. Oral food challenges are not necessary if infants or young children experiences several acute episodes in the past 6-12 months and their symptoms resolve when the offending food is avoided in the diet.

Anna Nowak-Wegrzyn, MD
Associate Professor of Pediatrics
Mount Sinai School of Medicine
Jaffe Food Allergy Institute
Tel.:  212-241-5548
Dr. Nowak is a clinician and clinical researcher at the Jaffe Food Allergy Institute. Her clinical research interests, funded by in part by the National Institutes of Health and Food Allergy Initiative, include: egg and milk allergy, food-induced anaphylaxis treatment and risk factors, diagnostic issues in food allergy, food protein-induced enterocolitis syndrome and pollen-food allergy syndrome (oral allergy).