Food protein-induced enterocolitis and enteropathy — formative SAQs

SAQ 1 — The recurrent delayed vomiting collapse (10 marks, 15 minutes)

Prompt: A 7-month-old is brought to the emergency department pale, lethargic and vomiting repetitively. Two hours earlier the child ate rice cereal for the second time; the identical pattern occurred two weeks ago after rice. There is no urticaria, wheeze or swelling. Outline your diagnosis, the criteria that support it, the dangerous mimics to exclude, and your immediate management. [1]

Model answer

• Diagnosis: acute food protein-induced enterocolitis syndrome (FPIES) to rice, a non-IgE-mediated, cell-mediated food allergy. The clue is the delayed, repetitive vomiting one to four hours after a trigger food, recurring with the same food, with pallor and lethargy and no classic IgE-mediated skin or respiratory features. [1] [2]
• Criteria: the 2017 international consensus major criterion is vomiting one to four hours after ingestion without classic IgE features. Support with the minor criteria present here — a repeat reaction to the same food, lethargy, pallor, and an emergency presentation — of which three or more are required. [1]
• Mimics to exclude: sepsis (do a septic screen on a first or atypical presentation), intussusception and appendicitis, and, in the premature or very young infant, necrotising enterocolitis; the recurring food-timed pattern and the sterile cultures point to FPIES. [1] [11]
• Immediate management: assess airway, breathing and circulation; secure intravenous access; send a blood gas, full blood count, electrolytes and glucose; give repeated 20 mL/kg boluses of isotonic crystalloid until perfusion is restored; give intravenous ondansetron for ongoing vomiting and consider a single dose of methylprednisolone; correct acid-base and electrolyte disturbance; observe until the child is stable. [1] [8]
• Disposition: admit the dehydrated or acidotic child; provide strict avoidance of rice and its cross-reactive grains, a written FPIES action plan, and referral for a medically supervised oral food challenge to confirm and to test tolerance. [1]

SAQ 2 — The faltering formula-fed infant (10 marks, 15 minutes)

Prompt: A 6-week-old, exclusively cow's-milk-formula-fed infant has three weeks of intermittent vomiting, watery stools and a fall across two weight centiles. The feed is changed to an extensively hydrolysed formula and the symptoms resolve over several days. Discuss the diagnosis, why the tests are negative, the substitute-feed choice and the role of the oral food challenge. [1]

Model answer

• Diagnosis: chronic food protein-induced enterocolitis syndrome to cow's milk, arising from ongoing regular ingestion, presenting with intermittent vomiting, diarrhoea and faltering growth that resolve over several days once the trigger is removed. [1] [3]
• Why tests are negative: FPIES is T-cell-mediated rather than antibody-mediated, so skin-prick tests and specific immunoglobulin E are negative in classic disease and cannot confirm it; a positive immunoglobulin E would represent sensitisation, not the mechanism. The diagnosis is built on the consensus criteria and confirmed by resolution on elimination and recurrence on a medically supervised oral food challenge. [1] [6]
• Substitute feed: an extensively hydrolysed formula is first-line, escalating to an amino-acid formula if symptoms persist; soy is used with caution in young infants because a meaningful proportion of cow's-milk-FPIES infants also react to soy. [1] [6]
• Oral food challenge: the medically supervised oral food challenge is the gold standard for confirmation and for tolerance testing, performed with intravenous access available, graded dosing over about thirty minutes, and observation for four to six hours because the reaction is delayed; a negative challenge permits home reintroduction of the food. [1] [8]
• Prognosis and plan: most children outgrow FPIES, with cow's-milk FPIES resolving earliest, so tolerance is assessed at intervals by supervised challenge under allergy and dietetic supervision, with a written action plan for the interim. [1] [3]