Results of the oral egg-challenge test performed on two different groups of children. One group with a history, suggestive of allergic reaction with egg intake and the other group sensitised to hen’s egg without previous egg intake
Next Document Allergol Immunopathol (Madr). 2010;38:233-40.
Egg allergy is an adverse immune-system reaction of an IgE-mediated type, which can happen in children after egg intake and several times after their first egg intake.Objectives
Compare the results of the oral egg-challenge test in two groups of egg-sensitised children, with and without prior intake.Patients and methods
Retrospective study of two egg-sensitised groups (72 subjects).
Group 1: 22 children without prior egg-intake.
Group 2: 50 children with a clinical history of adverse reactions after egg intake.
Skin prick tests, egg-white specific IgE (sIgE) and yolk specific IgE, were performed on all children. The oral egg-challenge tests were performed after a period of egg-avoidance diet and when egg-white specific IgE levels were lower than 1.5KU/L.Results
31.8% of the children in Group 1 did not tolerate egg-intake whereas 38% of the children in Group 2 did not tolerate egg-intake. Egg-avoidance periods lasted 19.5 and 18 months, respectively.
Egg-white specific IgE levels went down in both groups after an egg-avoidance diet. No statistically significant differences were found between the groups and the positivity of oral egg-challenge test.Conclusions
No statistically significant differences were found in the behaviour of the two groups studied.
Given the high risk of adverse reactions, it was recommended that any egg-introduction tests were to be performed in a hospital environment on the children who were sensitised to hen’s egg (including children without prior egg intake).
Egg is a foodstuff that often produces allergies in early childhood due to its high protein-content.
Egg allergy is an adverse reaction that has an immuno-pathogenic mechanism. Egg allergy prevalence is still unknown. It ranges from 0.2% to 7% in the meta-analysis by Rona et al.1 According to the outcome of the study “ALERGOLOGICA 2005”2 carried out by SEAIC, the most frequent allergy-producing foods in children younger than seven years of age in Spain are egg; milk; fish; and nuts. In older children the culprit is vegetables.
Egg-sensitisation in children without prior egg-intake has often been detected in tests for atopic dermatitis (AD) and cow’s milk-protein allergy.
Several IgE-mediated reactions 3,4,5,6 were described after first intake, which points to a prior sensitisation that can have been produced by different means; either by intrauterine (in utero) sensitisation, due to the fact that egg-specific IgE 7 has been found in cord blood, or by means of breast-feeding.8 A third means could be objects that have been contaminated with egg particles, such as cooking equipment and toys.
There is every likelihood that children who suffer from egg allergy will have a history of AD.9,10,11,12 This pathology often begins in the second or third month of life when the baby is being breast-fed. That is to say that it happens during lactation, and thus there is no relationship to egg-intake.5
Once there is an indication of immediate egg allergy from a patient’s preliminary case history, egg sensitisation must be demonstrated. This can be achieved by skin prick tests (SPT) and/or in vitro tests. The SPT is the best means of diagnosing egg allergy owing to its high sensitivity (73–100%), although it has a lower specificity. Egg SPT negativity might rule out egg allergy in most cases due to its highly negative predictive...
Read the complete contents of this article
Access all articles in the magazine Portuguese Journal of Public Health, without limitation.