FPIES (Food Protein Induced Enterocolitis Syndrome)

What is FPIES?

Food protein induced enterocolitis syndrome (FPIES) is a severe form of non-IgE mediated food allergy.

How does FPIES present?

FPIES most often presents in the first year of life with acute reactions following the introduction of formula or solid foods. Acute FPIES reactions typically occur 1-6 hours after ingestion of a trigger food or formula.

Reactions cause repetitive vomiting (often large volume and projectile, may become bilious) which may be accompanied by marked lethargy, floppiness and pallor.

Some infants/children will recover from an acute FPIES reaction with oral rehydration at home, but some reactions progress to hypotension and shock.

There are no associated rashes, swelling or respiratory symptoms. There may be diarrhoea, usually 5-10 hours after ingestion of the trigger.

Blood tests may show non-specific abnormalities, including a raised white blood cell count (neutrophilia) and platelet count. Metabolic acidosis may be present in severe cases.

There are no specific radiological findings.

What foods can trigger FPIES?

FPIES can be triggered by a large range of foods, including foods not classically considered allergenic. In the UK more common FPIES trigger foods include the following.

• Cow’s milk
• Hen’s egg
• Fish
• Oats
• Rice
• Banana
• Avocado
• Sweet potato

The majority of affected children have only one or two trigger foods, but around 5% have multiple (3 or more) trigger foods.

Reactions do not always occur on the first ingestion of a trigger food; it may take several ingestions before a reaction occurs.

How to diagnose FPIES

There are no diagnostic tests specific for FPIES, and skin prick tests are usually negative. Diagnosis is primarily based on a clinical history of characteristic signs and symptoms, with improvement after withdrawal of the suspected trigger food.

Medically supervised oral food challenges can be carried out if there is diagnostic uncertainty but are not often required.

FPIES may coexist with IgE-mediated allergy to other foods and/or non-IgE allergies with more chronic symptoms.

How to manage FPIES

Vomiting in acute reactions usually responds to treatment with ondansetron.

If the infant/child is deteriorating despite attempts to rehydrate them orally with clear fluids or breast milk, treatment with intravenous fluids and other supportive treatment may be required.

There is no role for antihistamines or intramuscular adrenaline in management of acute FPIES reactions.

Ongoing management of FPIES involves strict avoidance of trigger foods, and considered introduction of new foods, preferably under specialist dietetic supervision.

What is the prognosis for FPIES?

The prognosis for children with FPIES is very good and the majority outgrow it by 5 years of age. There are a small number of teenagers and adults with FPIES, particularly triggered by sea food.