What is FPIES?

Food Protein-Induced Enterocolitis syndrome, or FPIES for short, is uncommon, occurring in 1 in 300 children. It usually starts in the first year of life but can start in later childhood or even in adulthood. It is an intolerance to specific foods, typically associated with profuse vomiting, which can cause dehydration and shock.

The exact cause is currently unclear. FPIES is not a classical allergy in that it is not associated with hives, swellings, or wheeze. Standard blood and skin prick IgE-based allergy tests are not helpful. Adrenaline auto-injectors are not indicated as they do not reverse the symptoms.

What are the symptoms of FPIES?

Symptoms do not occur immediately after eating the food, but rather 1 – 4 hours later. The most common symptom is repeated and profuse vomiting.  1 in 5 children can become floppy, pale, and cold (shocked) because of fluid loss. Diarrhoea may follow within 6 – 8 hours. Symptoms usually resolve within 24 hours. There are no rashes or breathing problems.

Children are well between episodes and grow normally. FPIES can be confused with food poisoning, gastroenteritis, bowel obstruction, or sepsis, but in these diseases, giving the food again will usually not cause repeated symptoms.

In formula fed infants, FPIES can cause chronic watery, sometimes bloody diarrhoea, colic, and intermittent vomiting, associated with weight loss (chronic FPIES). Symptoms may take several days or weeks to resolve after removing the food from the child’s diet.

How serious is FPIES?

FPIES does not cause anaphylaxis and therefore an adrenaline auto-injector will not help. There have been no reported deaths from FPIES. The vomiting often resolves after 1 – 2 hours without the need for specific treatment, but in 1 in 5 children profuse vomiting may cause fluid loss leading to the child becoming floppy, cold, and pale (shocked). These children will need treatment with intravenous fluids by emergency services.

What foods trigger FPIES?

Any food can cause FPIES. The most common trigger varies with age of introduction of the food. In infants and children, cow’s milk, soya, rice, and oats are common causes, followed by egg, fruits, and vegetables. In older children, fish may cause FPIES. Legumes (peanuts, peas) are an uncommon cause. FPIES is rare in children exclusively breast fed. Three quarters of children will only react to one food and the rest will react to more than one.

Cow’s milk and soya are the most common causes of chronic FPIES.

How do we diagnose FPIES?

The diagnosis is based on a history of repeated episodes of profuse vomiting a few hours after the child eats a food or foods.  Standard allergy tests such as blood IgE-based tests and skin prick tests are of no use in diagnosing FPIES.

To confirm whether a specific food is causing FPIES, or to decide if the child has outgrowth the problem, a hospital challenge will be recommended. Children need to be observed for at least 4 hours after eating the food. In some hospitals a canula is inserted in case the child needs intravenous fluids.

How should you manage a reaction?

In many cases the vomiting will resolve by itself without seeing a doctor. However, if the child becomes floppy, pale and cold (shocked), they should lie flat, with their legs raised. Urgent medical attention should be sought as they will need hospital admission for intravenous fluids, and a medicine (typically ondansetron) to help stop the vomiting.

The reaction is not due to anaphylaxis and injection of adrenaline e.g. an EpiPen will not help.

Children should avoid the food triggering the reaction, until it has been confirmed that they have outgrown the problem.

Who needs to know about this allergy?

It is important to inform the nursery/school. Any other carers such as grandparents, relatives and school friends’ parents will also need to know.

Is FPIES life long?

Many infants with FPIES will outgrow the problem 12-18 months after their last reaction; most by the age of 2 years old. FPIES to liquids may resolve at an earlier age to solid foods. An oral challenge, usually in hospital, is recommended to confirm that the problem has resolved.