Egg, wheat, soy, fish and shellfish allergy: Case

This girl has confirmed IgE-mediated egg allergy with a favourable prognostic profile, complicated by an over-restrictive elimination diet that is now affecting her growth. Her convincing immediate reaction to egg, a skin-prick test of 6 mm and an egg-white specific IgE of 12 kU/L establish egg allergy, while her low ovomucoid (Gal d 1) specific IgE indicates heat-labile, baked-egg-tolerant allergy that is likely to resolve. The removal of wheat, soy, fish and shellfish is unjustified and is the likely cause of her growth faltering, and the central management task is to confirm egg as the sole allergen, restore the other foods, introduce baked egg, and provide a focused action plan. [1]

Clinical findings

The key findings are the atopic background of moderate flexural eczema, the reproducible immediate reaction to egg, and the concordant testing that confirms egg allergy. The low ovomucoid IgE in the face of a positive whole-egg IgE is the discriminating piece: it tells the clinician that her allergy targets the heat-labile ovalbumin rather than the heat-stable ovomucoid, which predicts baked-egg tolerance and a higher likelihood of resolution. The growth faltering from the 50th to the 25th centile is the red flag for the nutritional harm of the elimination diet and is itself a clinical finding that demands correction. [3]

The candidate should articulate the problem representation clearly: a pre-school child with eczema and confirmed but favourable-pattern egg allergy, on an unnecessary multi-food elimination diet causing growth faltering, who needs dietary restoration, a baked-egg challenge, and an action plan. This single statement tells the examiner the diagnosis, the prognostic subclassification, the iatrogenic problem, and the plan. [2]

Investigations

The skin-prick test of 6 mm confirms sensitisation, and above the 3 mm threshold it is clearly positive. The egg-white specific IgE of 12 kU/L places her in a moderate-probability range for true allergy, consistent with her history. The crucial refinement is component-resolved diagnostics: the low ovomucoid (Gal d 1) IgE of 0.8 kU/L against the raised whole-egg IgE indicates that her reactivity is to heat-labile proteins, predicting baked-egg tolerance. [1]

The gold standard confirmation of tolerance to baked egg is a supervised oral food challenge, which is the appropriate next investigation. The candidate should describe the challenge: incremental doses of extensively heated egg in a matrix such as a well-baked muffin, performed under medical supervision with resuscitation facilities, to confirm that she tolerates baked egg. The other foods need no further testing, because there is no history of reaction and removing them on the basis of an over-broad panel is the error to correct. [2]

Management

The management has four parts. First, dietary restoration: wheat, soy, fish and shellfish are reintroduced with dietetic support, because there is no evidence of allergy to them and their removal is the cause of her growth faltering. Second, the baked-egg ladder: if the supervised baked-egg challenge is tolerated, she consumes baked egg regularly to build tolerance, advancing toward less-heated forms over months under guidance, because cohort data show that baked-egg consumption accelerates tolerance. Third, a safety-net: a written ASCIA anaphylaxis action plan and an adrenaline autoinjector (0.15 mg, as she is under 20 kg), because she has had a systemic reaction. Fourth, eczema control and asthma review, because atopic disease is her background risk profile. [2]

The candidate should be explicit that strict avoidance of all egg is no longer the goal if she tolerates baked egg. Regular baked-egg intake is the active-tolerance intervention, and the family should be supported to maintain it rather than fearful of it. A dietitian coordinates the reintroduction of the other foods and the energy, protein, calcium and iron adequacy of the overall diet, with growth monitored to confirm recovery. [1]

Recovery and prognosis

Her prognosis is favourable. Egg allergy resolves in roughly half of children by age six in the HealthNuts longitudinal cohort, and baked-egg-tolerant children with a low ovomucoid IgE resolve faster than those with heat-stable, baked-egg-reactive allergy. The plan is to trend her egg-white specific IgE annually, to continue the baked-egg ladder, and to perform a supervised challenge to less-heated egg when the tests and the baked-egg tolerance suggest resolution is likely. [3]

The growth faltering should reverse once the elimination diet is corrected and a nutritionally complete diet is restored, and her centile should be followed to confirm recovery. The family should be counselled that egg, wheat and soy allergies are usually outgrown whereas fish and shellfish, had she been allergic, tend to persist; in her case, with egg as the sole allergen and a favourable pattern, the outlook is one of expected resolution. [1]

Communication

The communication skill the exam rewards is a specific, written, behaviour-based plan that corrects the family's understandable over-restriction without dismissing their anxiety. The candidate should tell the family plainly that their daughter is allergic to egg only, that the other foods are safe to bring back, and that most children with her pattern of egg allergy outgrow it. The action plan and the adrenaline autoinjector are explained concretely, and the family is given a clear timetable for re-testing and the baked-egg challenge. Offering the family the chance to repeat back the plan confirms understanding and protects against both a late reaction and continued unnecessary restriction. [2]