What is FPIES?

Food Protein-Induced Enterocolitis Syndrome (FPIES), is a rare, severe delayed food allergy, that causes profound vomiting and diarrhea. In some cases, acute symptoms can include lethargy, vomiting bile and can progress to dehydration and shock brought about by low blood pressure and poor blood circulation. FPIES reactions are triggered by the proteins found in potentially all food. The most common triggers include milk, soy and grains often thought to be hypo-allergenic (such as rice and oats). Many children with FPIES have more than one food trigger.

FPIES is Not a Typical Allergy

Everything you know about allergies doesn't apply. Most food allergy reactions happen soon after coming in contact with an allergen whereas FPIES reactions are delayed, occurring hours after eating the offending food. This obviously makes it harder to diagnose. In most allergies, the immune system overreacts to the allergen by producing Immunoglobulin E (IgE) antibodies however, FPIES reactions are thought to be cell-mediated. Because of this, traditional allergy diagnostic tests often show up negative, so there is no test for FPIES. Many allergies present with hives, swollen tongue or anaphylaxis, whereas FPIES involves the GI system. FPIES can be thought of as anaphylaxis of the gut. In fact, certain features overlap with food protein-induced enteropathy and protocolitis whereas others overlap with anaphylaxis. 

Diagnosing FPIES

FPIES often appears in infancy, usually when a baby is introduced to formula or solid food. Because symptoms of FPIES mimic those of a gastrointestinal virus, and because there are no diagnostic tests, FPIES often goes undiagnosed or misdiagnosed for a long time, leaving the family to try to make sense of the symptoms and a leaving a child sick and in pain. 

Management of FPIES

The only way to manage FPIES is to determine what foods trigger a reaction and strictly avoid them. This means that introduction of foods for babies with FPIES is a slow and lengthy process, often wrought with daily anxiety and requires patience, fortitude and the keeping of detailed logs.

Treatment of FPIES Acute Reactions

If a severe reaction does occur, treatment of the dehydration to prevent shock is required, that is, fluids must be given to counteract fluid loss from vomiting and diarrhea. In more severe cases, intravenous Ondansetron or steroids might be given.

Age-dependency

FPIES usually resolves with time, often as tested by an Oral Food Challenge, generally in a hospital setting. The later you wait to introduce high-risk foods, the more likely the child will be able to tolerate them.