Food protein-induced enterocolitis syndrome (FPIES) is an unusual type of food allergy. It is much less common than IgE-mediated food allergy, and usually only occurs in babies and very young children. FPIES is caused by an allergic reaction to a food which causes inflammation of the small and large intestine. It differs from normal food allergy as:
- It is usually a delayed reaction
- Symptoms are normally limited to the gut (there is no skin rash or swelling)
- It is not caused by IgE antibodies
- It is not associated with anaphylaxis, so adrenaline is NOT used to treat the reaction
In general, the reaction begins around 2–4 hours after eating the trigger food. The child develops profuse vomiting, frequently followed by diarrhoea or loose stools which can last for several days. Occasionally a shorter time frame may be seen. In the most severe FPIES reactions, vomiting and diarrhoea can cause serious dehydration. These children may become pale, floppy, have reduced body temperature and/or blood pressure during a reaction. These children may be mistaken as having an infection, as their blood tests may show an increased white cell count which is often seen in infection.
FPIES is not caused by IgE antibodies, so children experiencing reactions do not develop itchy swollen skin, rashes or facial swelling. However, it is possible for a child with FPIES to also have other allergies including food allergies which do involve IgE antibodies.
Sometimes, children with FPIES have more mild reactions, and if they continue to eat the trigger foods, the allergy can result in poor growth.
The most common triggers are cows’ milk (dairy) and soy. However, almost any food can cause an FPIES reaction, including rice, cereals such as oats, certain vegetables (frequently from the legume family) and meats such as chicken and turkey.
Some children have FPIES to more than one food protein. For example, some children reactive to cows’ milk have been noted to react to soy and some reactive to rice have also reacted to oats.
There is no allergy test which can confirm a diagnosis of FPIES. Skin tests and blood tests to measure IgE levels do not help, as the reaction is not caused by IgE antibody. This can make FPIES difficult to diagnose. Your doctor may recommend an oral food challenge when the history is not clear, or if foods from a similar food group are being introduced into the diet of a child who has FPIES. These challenges should always take place under specialist supervision in a hospital.
The only treatment for FPIES is to avoid the trigger food. Your doctor will advise as to how to alter the diet to achieve this, and you may receive advice from a dietitian if the foods to be removed include a major food group.
There is no specific treatment for a child during an FPIES reaction. However, they often respond to intravenous (IV) fluids, due to the dehydration. Most families of children with FPIES will be given a letter to present to emergency departments explaining their child’s condition and the appropriate treatment.
There is no role for the use of adrenaline devices in the management of FPIES.
Most children outgrow FPIES by the time they are about three to four years of age. The best way to determine whether a child has outgrown their FPIES is for them to have an oral food challenge; this should always take place under specialist supervision in a hospital.