Understanding FPIES
From time to time, we like to write about the rarer forms of food allergy. We’ve covered Eosinophilic Esophagitis, Oral Allergy Syndrome, and allergies to red meat and water! Today’s blog topic will cover another lesser-known, but very serious food allergy: Food Protein-Induced Enterocolitis Syndrome (FPIES for short).
What is FPIES?
FPIES is a non-IgE immune system reaction to food that affects the gastrointestinal (GI) tract. IgE stands for the antibody immunoglobulin E, and most allergic reactions (think the top eight most common food allergies) involve this antibody. FPIES is cell-mediated, which results in a delayed allergic reaction.
Notably, unlike typical food allergies, an FPIES allergy does not show up on standard allergy tests.
FPIES baby
FPIES reactions often show up in the first weeks or months of a child’s life. Sometimes the child may be a little bit older if they’ve been exclusively breastfed. First reactions often occur when introducing solid foods, such as infant formulas or cereals, which are typically made with dairy or soy.
FPIES trigger foods
Rice and oats are the most common solid food triggers for infants. Other reported triggers include milk, soy, barley, sweet potato, squash, green beans, peas, and poultry. As with any food allergy, some children may only react to 1-2 foods, while others may react to several. Any food protein can be a trigger.
If you’re having trouble ensuring your child is getting the proper nutrients he/she needs because of their FPIES diet, make sure to talk to your doctor. They may refer you to a dietitian that can help you map out a nutritional plan.
FPIES symptoms
FPIES can cause severe symptoms following the ingestion of a trigger food. Classic FPIES symptoms include diarrhea, severe vomiting, and dehydration. Symptoms range from mild (e.g., an increase in reflux and runny stool) to life-threatening (e.g., shock). Notably, there is usually a 2-3 hour delay between ingestion and symptoms.
Importantly, many infants who are eventually diagnosed with FPIES are initially suspected to have a severe infection or sepsis based on symptoms.
FPIES diagnosis
FPIES cannot be detected with traditional allergy testing methods, such as skin prick or blood tests that measure IgE antibodies. It is accordingly tough to diagnose. You will want to consult a doctor—often an allergist and/or a gastroenterologist.
Researchers are currently looking to atopy patch testing (APT) for its effectiveness in diagnosing FPIES. APT involves placing the trigger food in a metal cap, which is left on the skin for around 48 hours. The skin is then observed for symptoms in the days following removal.
The outcome of APT may also determine if the child is a potential candidate for an oral food challenge: the gold standard for food allergy diagnosis.
The silver lining for FPIES
The good news is that FPIES usually resolves with time! Many children outgrow FPIES by age 3, allowing kids to introduce the offending foods back into their diet over time. With proper medical attention and a personalized dietary plan, children with FPIES can grow and thrive!
- Meg and the Allergy Amulet Team