What is FPIES?
FPIES stands for Food Protein-Induced Enterocolitis Syndrome. It is a type of food allergy that involves a different part of the immune system from the immediate (IgE-mediated) allergies detected by skin prick tests and specific IgE blood tests. FPIES mainly affects infants and young children, though it can occur at any age.
Unlike immediate food allergy, typical FPIES reactions do not cause hives, swelling or wheezing. The reaction is delayed and primarily affects the gut.
Symptoms and Timing
Acute FPIES episodes typically involve repeated, profuse vomiting beginning around one to four hours after eating the trigger food. The vomiting can be severe and prolonged. Other features may include:
- Pallor — the child may look very pale
- Marked lethargy or floppiness
- Diarrhoea, which may appear several hours after the vomiting
Severe reactions can cause dehydration and, in some cases, shock. The child may appear seriously unwell. If your child becomes very pale, floppy, difficult to wake or collapses, call 999 immediately.
Because FPIES does not typically cause hives, swelling or breathing difficulty, it can be mistaken for a viral illness, gastroenteritis or other conditions. This can delay diagnosis.
How FPIES is Assessed
Diagnosis of FPIES depends mainly on the clinical history and exclusion of other causes. There is no single diagnostic test. Assessment involves:
- A detailed history of episodes — timing, foods eaten, symptoms, severity and recovery
- Review of the child's growth, diet and feeding history
- Consideration of other possible causes
- Allergy testing where a separate or coexisting IgE-mediated allergy is suspected
Dr Anandarajan provides outpatient assessment for children with suspected FPIES in Belfast. Appointments are available at Kingsbridge Private Hospital and Ulster Independent Clinic. No GP referral is required.
Why Routine Allergy Tests May Be Negative
Skin prick tests and specific IgE blood tests detect IgE-mediated allergy. Because FPIES involves a different immune mechanism, these tests are typically negative in children with isolated FPIES. A negative allergy test does not rule out FPIES.
A clinician may request skin prick testing or specific IgE blood tests if there is a clinical suspicion of a separate or coexisting IgE-mediated allergy alongside FPIES.
Management and Nutritional Support
Management of FPIES centres on identifying and avoiding the trigger food or foods. This requires careful dietary planning, particularly in infants who may be relying on a limited number of foods.
Dietitian support may be needed to ensure the child's nutritional needs are met while avoiding triggers. Dr Anandarajan works with dietitians where dietary advice or nutritional support is required. Onward specialist referral is arranged where clinically indicated.
Each child's management plan is individual. The foods avoided, the degree of restriction and the follow-up arrangements depend on the clinical assessment.