A child who eats an egg

Allergenic component tests transform the approach of food allergies but show their limits. Consequently, illustrated by the case of a child who develops anaphylaxis despite tests predicting tolerance to cooked eggs.

Over the past 20 years. Nevertheless, allergological diagnosis, mainly that of food allergies (AA) has been enriched with new diagnostic tools, in particular diagnosis based on allergenic components or multialergenic tests (TMA). Meanwhile, It makes it possible to clarify the awareness scheme of allergies. Similarly, in particular that of multiallergic/multisensitized, to help differentiate crossed reactivity and co-sensitization, and to exclude an allergy or, on the contrary, to reveal unexpected awareness/allergies. Moreover, The dosages of specific serum IgE (IGES) directed against molecular allergens are mainly interesting to better understand certain clinical situations. Nevertheless, In current practice. Therefore, they have less interest in the diagnosis itself, and almost no interest in the care of the patient. Similarly, child who eats egg

A case that illustrates the limits of the egg TMA

The case reported by Knight et al. Attracts attention to the possibility of discrepancy between tests to whole allergens and TMA. Observation concerns a 13 -month -old infant admitted for an oral provocation test (TPO) to a flat egg. It had already benefited from AA screening because of its eczema. with a dosage of the Igges showing IgE levels specific to the egg white of 96.9 ku/L, anti-ovomucoid IgE less than 0.10 ku/l and anti-ovalbumin IgE greater than 100 ku/l. No skin test had been carried out.

Although having no history of systemic allergic reaction to eggs. he had presented, at the age of 8 months, vomiting immediately after the consumption of a third of egg.

According to the analysis of the results of a TMA. this awareness seemed to incriminate the thermolabile ovalbumin and not the ovomucoid (thermostable protein), which child who eats egg suggested that a denaturation by heating would lead, in this child, tolerance to egg proteins.

The results of the TMA were discussed with the family. and it was estimated that the child was likely to tolerate denatured egg proteins.

An oven -cooked egg was planned: during this test. the patient consumption about half a muffin containing a third of egg before developing abundant agitation and vomiting, requiring the rapid adrenaline injection into the anterolateral region of the thigh, resulting in rapid improvement in symptoms.

The young patient was finally deemed intolerant with distorted eggs. he was advised to strictly avoid any food containing egg proteins.

A non -dichotomous probabilistic approach

Before the component tests. the IgE against the whole egg served as a reference to diagnose allergy. A rate> 7 Kua/L predicts 98 % of allergic reactions. Egg proteins (ovomucoid, ovalbumin, ovotransferrin, lysozyme) contain specific epitopes. Some are destroyed by heat, others child who eats egg resist like those of the ovomucoid. Most allergic patients tolerate the cooked eggs, promoting the resolution of the allergy in more than half of the cases. However, even with tests of negative components, anaphylactic reactions remain possible during provocation tests. IgE tests modify the probabilities but do not guarantee the diagnosis. Interpretation requires a probabilistic, non -dichotomous approach. The early introduction of allergens is now recommended for prevention, especially in children at atopic risks.