Q: My grandson has been a very sick little boy who has suffered bouts of severe diarrhea and vomiting. At last his parents got a diagnosis for him — a type of allergy called FPIES, and they’re now avoiding several foods including milk and soy. It seems it’s not a “typical” food allergy. Could you explain what it is?
Dr. Sicherer: FPIES stands for food protein-induced enterocolitis syndrome, which is a type of food allergy because the immune system is involved. However, allergy skin and blood tests are usually negative.
FPIES symptoms are unlike those of typical allergies. You are likely familiar with allergic reactions having skin and airway symptoms within minutes of consuming the food. In contrast, FPIES symptoms mostly involve the gut, with severe vomiting that starts about two hours after the problem food is eaten. A child can appear very ill, pale or blue, weak, and may have low blood pressure. Diarrhea may come on later.
These symptoms mimic a serious infection, and if blood tests are done they may also suggest an infection because the white blood cell count goes up. Since typical allergy tests are negative, and because of the delayed symptoms, the syndrome is often misdiagnosed until a pattern is observed. Sometimes the vomiting and diarrhea are persistent, rather than episodic, if the food has been eaten without interruption.
The most common foods causing FPIES are milk, soy, oats and rice, but many other foods can also be triggers. Treatment of a severe reaction requires intravenous fluids, and doctors may use other medications such as steroids and anti-nausea treatment. Unlike typical allergy, antihistamines and epinephrine are not commonly used.
The good news is that the allergy usually resolves in early childhood. Both diagnosis and confirmation of resolution may require medically supervised feeding tests. In some children, allergy tests can become positive to certain foods and symptoms may include those typical of allergy with skin, gut or airway symptoms.
Dr. Scott Sicherer is a practicing allergist, clinical researcher and professor of pediatrics. He is Chief of the Division of Allergy and Immunology, Jaffe Food Allergy Institute, at the Icahn School of Medicine at Mount Sinai in New York. He is also the author of Food Allergies: A Complete Guide for Eating When Your Life Depends On It.