User:Urgency of now/Food protein-induced enterocolitis syndrome

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Food protein-induced enterocolitis syndrome (FPIES) is a systemic, non IgE-mediated response to a specific trigger within food – most likely food protein. FPIES may present either as an acute or chronic form. In its acute form, FPIES presents with vomiting that typically begins 1 to 4 hours after trigger food ingestion, alongside paleness of the skin, lethargy, and potentially blood-tinged diarrhea. In the severe form of acute FPIES, continued vomiting may cause severe dehydration or hypotensive shock-like state, requiring hospitalization. In its chronic form, chronic exposure to trigger foods results in chronic or episodic vomiting, poor weight gain, failure to thrive, and watery or blood-tinged diarrhea. FPIES can potentially develop at any age, from infancy to adulthood, but most commonly develops within the first few years of life and resolves in early childhood. Atypical FPIES presents with evidence of specific IgE-sensitization via positive specific serum or skin IgE testing to trigger foods; atypical FPIES may prolong time to disease resolution or increase risk of conversion to IgE-mediated food allergy.

Epidemiology

To date, various studies have estimated FPIES incidence to be between 0.015% and 0.7%. However, establishing the true prevalence of FPIES has been hindered by the scarcity of population-level epidemiological studies, the relatively recent establishment of uniform diagnostic criteria (established in 2017), and under-diagnosis due to disease rarity and lack of awareness. A 2019 United States population-level survey estimated a FPIES prevalence of 0.51% in children and 0.22% in adults. Similar prevalences in children have been found in population-level estimates from Israeli and Spanish studies.

Diagnosis

Diagnosis is clinical, based on reported symptoms, as specific IgE and skin prick tests are typically negative (except in cases of atypical FPIES). No laboratory test or procedure is currently recommended for FPIES diagnosis. The underlying pathophysiology of FPIES is not understood at this time, though it is generally understood to be non-IgE mediated. One study found that in patients with non-IgE mediated food allergy, Th2 lymphoproliferative responses were similar to that of patients with IgE-mediated allergies, suggesting an underlying T-cell mechanism of action.Another study found elevated IL-17 markers, elevated innate inflammatory markers, and increased T-cell activation after FPIES reaction.

Acute FPIES

Per international consensus guidelines published in 2017 by the American Academy of Allergy, Asthma and Immunology, acute FPIES diagnosis may be established in a patient who meets the following major criterion and at least three minor criteria:

Major criterion: Vomiting approximately 1-4 hours following oral consumption of a suspected trigger food, without signs of classic IgE-mediated skin or respiratory allergic symptoms (i.e. hives, itchy skin, stridor, wheezing, tightness in throat).

Minor criteria:

• Second episode of vomiting after eating same food which provoked first episode of vomiting
• Repetitive vomiting 1-4 hours after eating a different food
• Significant lethargy
• Pallor (paleness of skin)
• Required emergency department or urgent care visit due to reaction
• Required IV fluid administration due to reaction
• Diarrhea within 24 hours of consuming trigger (may or may not be bloody)
• Hypotension
• Hypothermia

Current acute FPIES guidelines further divide acute FPIES reactions into mild to moderate and severe disease presentation. Mild to moderate disease typically presents with 1-3 episodes of vomiting around 1-4 hours after trigger ingestion, reduced activity level pallor, which usually self-resolves without medical intervention, and/or mild diarrhea. Severe disease typically presents with 4+ episodes of bilious and/or projectile vomiting within ~1-4 hours, along with possible lethargy, abdominal distension, dehydration, diarrhea, hypotension, hypothermia, and/or need for IV rehydration. Laboratory studies might reveal hypoalbuminemia, anemia, eosinophilia, and an elevated white blood cell count with a left shift. Over half of patients experiencing an acute FPIES reaction may develop thrombocytosis (platelets >500x10⁹/L). Methemoglobinemia and metabolic acidosis have been reported in both chronic and acute FPIES. Endoscopy may reveal a gastric erythema, edema, mucosal friability, and gastric antral erosions.

Differential Diagnosis

and the exclusion of other disorders that present similar clinical features, such as infectious gastroenteritis, celiac disease, inflammatory bowel disease, necrotizing enterocolitis, food protein-induced enteropathy, food protein-induced proctocolitis, and eosinophilic gastroenteritis, among others.

Management

Avoid feeding affected individuals the foods known to trigger an allergic response. Cow's milk, soy, and cereal grains are the most common trigger foods, but other foods have been reported including eggs, meats (poultry, beef, pork), seafood (fish, shrimp, mollusks), peanut, potatoes, nuts, and fruits (apple, pear, banana, peach, watermelon). The list of potential food triggers is varied and can be somewhat region specific. There are also cases of FPIES being transmitted through foods in breast milk in rare occasions. During an acute FPIES episode, ondansetron or infacol may be used to control symptoms in children over 6 months of age. Many breastfeeding mothers either eliminate the food from their diet although this is not always necessary or switch to an extensively hydrolyzed or elemental formula if there is a concern about cow's milk being an offending culprit. Some children tolerate soy based formulas if they have FPIES to cow's milk but many do not.

Data regarding time to FPIES resolution varies significantly, and appears to depend on factors such as the specific food trigger and whether it is atypical FPIES. On balance, available data suggests that a majority of FPIES cases to common trigger foods (cow's milk, rice, oat, soy) resolve by age 5, if not sooner.