Food Protein-Induced Enterocolitis Syndrome, or FPIES, is a severe food allergy primarily affecting the gastrointestinal system. Unlike many typical food allergies that trigger immediate reactions involving IgE antibodies, FPIES is a non-IgE mediated condition. This distinction means its symptoms are delayed and often mimic other illnesses, making it a unique and often misunderstood allergic disorder.
What FPIES Is
FPIES is an immune reaction within the digestive tract to certain food proteins. Unlike typical food allergies, this immune response does not involve IgE antibodies, which cause immediate reactions. Instead, FPIES involves other immune cells that cause inflammation in the intestines.
This condition primarily affects infants and young children, often appearing in the first year when milk, soy, or solid foods are introduced. Though less common, FPIES can also affect adults. The immune system mistakenly identifies food proteins as harmful, leading to gut inflammation and gastrointestinal symptoms.
Identifying FPIES Triggers and Symptoms
Recognizing FPIES can be challenging because symptoms are delayed and often resemble a severe stomach illness. Symptoms typically manifest one to four hours after ingesting the trigger food, making it difficult to connect the reaction to a specific food.
Common food triggers include cow’s milk, soy, rice, and oats, though almost any food can cause a reaction. Acute FPIES reactions primarily involve repetitive, profuse vomiting, often followed by severe diarrhea. Other signs include lethargy, pallor, and potential dehydration, sometimes requiring hospitalization for intravenous fluids.
Chronic FPIES, less common, results from frequent exposure. It causes subtle, ongoing symptoms like intermittent vomiting, chronic diarrhea, and poor weight gain.
How FPIES Is Diagnosed
Diagnosing FPIES is complex because traditional allergy tests, like skin prick tests or blood tests for IgE antibodies, are not effective; they yield negative results as the immune mechanism does not involve IgE. Diagnosis relies heavily on a detailed review of the child’s medical history and observed reactions to food.
Healthcare providers often recommend eliminating suspected trigger foods to see if symptoms resolve. The “gold standard” for confirming an FPIES diagnosis is a supervised oral food challenge (OFC). During an OFC, the suspected food is carefully reintroduced in a medical setting, with the patient monitored for several hours for any reaction. This controlled environment ensures any severe reactions can be managed immediately.
Managing FPIES and What to Expect
The primary approach to managing FPIES involves strictly avoiding identified trigger foods. For infants reacting to milk or soy formulas, hypoallergenic or elemental formulas may be recommended. Parents should work with their healthcare provider to develop an emergency action plan.
This plan includes instructions for managing accidental exposures, such as administering anti-vomiting medication and providing oral rehydration. In severe cases, intravenous fluids or corticosteroids may be administered in a medical facility. Most children outgrow FPIES, often by age three to five years, with reintroduction of trigger foods occurring under medical supervision via an oral food challenge.