Food Protein-Induced Enterocolitis Syndrome

Introduction:

Food protein-induced enterocolitis syndrome (FPIES) was initially recognized in the 1970s as a non-IgE-mediated food allergy characterized by delayed vomiting in newborns. FPIES, an often misdiagnosed and underdiagnosed disease, had its diagnostic code in 2015. There are two clinical phenotypes of FPIES: Acute FPIES and chronic FPIES.

What Are Acute FPIES?

• Acute FPIES responses are distinguished by short duration, delayed, and repeated vomiting. Parents frequently characterize their children as pale, sluggish, or limp. Diarrhea may develop in certain patients.

• Dehydration, which can lead to hypotension and shock if severe, is the most alarming possible result of an acute FPIES response. Anaphylaxis, cutaneous, or respiratory symptoms are not observed in IgE-mediated food allergies.

• When the offending food is consumed sporadically or after abstention, acute FPIES occur. They usually clear up within 24 hours, and patients are fine between bouts.

What Is Chronic FPIES?

• Chronic FPIES is most common in infants under four months fed cow's milk or soy formula and consume the offending food regularly and repeatedly.

• Chronic or intermittent vomiting, diarrhea, and low-weight growth or failure to thrive are all symptoms. Because other gastrointestinal disorders might manifest similarly, the presence of acute symptoms following a history of chronic symptoms validates the diagnosis of chronic FPIES.

• As a result, persistent FPIES is frequently identified after the other probable gastrointestinal illnesses have been ruled out.

What Is the Epidemiology?

• FPIES commonly appears between the ages of two to seven months when a formula or solid foods are introduced. Cow milk, cereals, soy in the USA and South Korea, and seafood in Italy and Spain are the most prevalent dietary triggers.

• Infants on formula often appear with cow milk and soy FPIES before six months, but infants on solid food present FPIES at a median age of five to seven months. In addition, grain FPIES often manifests faster than fish, egg, or poultry FPIES.

• According to the population, 65 to 80 percent of patients have FPIES to a single meal, most often seen with cow milk, whereas five to ten percent have responded to more than three foods.

What Is the Clinical Presentation of FPIES?

• Recurrent vomiting (families have observed more than one and beyond ten times in acute FPIES responses) often occurs one to four hours after administration of the food allergen. It is accompanied by lethargy, pallor, and limpness.

• In a subgroup of people, diarrhea may begin within five to ten hours. Symptoms can include dehydration and, in extreme cases, hypotension and hypovolemic shock (a condition in which excessive blood or loss of fluid occurs), necessitating immediate treatment.

• Patients may appear to have sepsis if they have hypothermia (persistent exposure to cold), methemoglobinemia, or acidemia.

• Chronic FPIES is associated with chronic or intermittent vomiting, diarrhea, and inadequate weight growth or failure to thrive. In addition, the symptoms can occasionally result in dehydration, shock, and hypoalbuminemia.

• Symptoms of chronic FPIES subside with the removal of the triggering food; however, again consuming the triggering food at later period results in an acute FPIES picture.

• The clinical phenotype is influenced by the onset of age, nationality, amount of allergen consumption, and IgE-mediated food allergy.

• Infants diagnosed with cow milk or soy FPIES under two months of age are more likely to develop diarrhea, blood in the stool, and failure to thrive in conjunction with vomiting. Older infants are more likely to develop only vomiting but not diarrhea.

• Symptoms of FPIES may appear in older children and adults with a delay in vomiting after eating fish, shellfish, or eggs.

What Is the Pathophysiology of FPIES?

• The pathophysiology of FPIES is unknown, although it is believed that a response to a dietary protein induces inflammation of the gut, which causes excessive intestinal permeability and a fluid shift, culminating in vomiting, diarrhea, and shock.

• Endoscopy and biopsy revealed nonspecific inflammation in the colon and ileum. T cells that recognize antigens and inflammatory cytokines have been identified.

• Subsequent research revealed the lack of a serum humoral response in FPIES but also reported elevated serum interleukin-8 and tryptase in active FPIES, suggesting neutrophil and mast cell participation.

• A further investigation by the same team found that positive FPIES oral food challenges activated innate immune cells in whole blood, such as monocytes, neutrophils, natural killer cells, and eosinophils.

How Is FPIES Diagnosed?

• Currently, no diagnostic laboratory test for FPIES is accessible due to the disease's unclear pathogenesis. Instead, a clinical history compatible with regular signs and symptoms is used to make a diagnosis, and symptoms are resolved by avoiding the potential dietary trigger.

• It is common for diagnosis to be delayed due to vague symptoms, a lack of experience with FPIES, and the fact that several solid food triggers, such as rice and oats, are generally not considered allergies. As a result, acute FPIES is frequently misdiagnosed as acute viral gastroenteritis or sepsis.

• If the dietary trigger is reintroduced, it should reproduce FPIES symptoms. Oral food challenges (OFCs) could be required if the diagnosis is unclear. Infectious gastroenteritis, sepsis, necrotizing enterocolitis, anaphylaxis, metabolic disorders, extreme lactose intolerance, neurologic diseases (cyclic vomiting), gastroesophageal reflux disease, and gastrointestinal obstruction are all possibilities for acute vomiting.

What Is the Management of FPIES?

• Acute FPIES responses should be treated individually based on severity. Favorable responses might be relieved by rehydrating orally. Moderate to severe responses necessitate intensive fluid resuscitation (10 to 20 ml per kg normal saline boluses) with successive boluses and dextrose-containing maintaining fluids as required.

• Although there is no evidence to support the use of steroids in FPIES responses, a single dose of intravenous Methylprednisolone (1 mg per kg, maximum 60 to 80 mg) may be administered in severe reactions for suspected inflammation. In severe responses, intravenous vasopressors are necessary for the management of shock.

• Oxygen, respiratory support, and methemoglobinemia adjustments may be utilized as required. Although epinephrine autoinjectors should be provided for people with IgE sensitization or IgE-mediated food allergy who are at risk of anaphylaxis, it is not advised as standard therapy for FPIES responses since it has no impact on emesis.

Conclusion:

FPIES, a non-IgE mediated food allergy characterized by delayed vomiting that often manifests in childhood, is becoming more well-known. Milk, soy, and wheat are the most prevalent casual foods. The age of onset, trigger foods, and country determines the phenotype of FPIES. FPIES is diagnosed clinically, and oral food challenges may be employed if the diagnosis is ambiguous. There are currently no diagnostic criteria for chronic FPIES, which commonly manifests as intermittent but progressive vomiting and diarrhea in young infants who regularly consume milk or soy formula. When evaluating chronic FPIES, screening out other gastrointestinal disorders is critical. The treatment for FPIES is supportive and focuses on removing the offending food and managing vomiting, dehydration, and shock. Patients with FPIES should have their development checked regularly.