TOPLINE

Food allergy continued to be uncommon at age 5 in children born in Dublin during Ireland's first COVID lockdown. Sensitization to airborne allergens increased from age 2 to age 5, whereas atopic dermatitis declined, and wheeze prevalence remained stable.

METHODOLOGY

• Researchers conducted a longitudinal observational study to evaluate whether the allergy patterns seen at age 2 in children born in Dublin during Ireland's first COVID lockdown (March-May 2020) were temporary or continued till age 5.
• A total of 209 children took part in the 5-year follow-up; of these, 180 children completed the questionnaire and attended the in-person visit, 28 completed the questionnaire only, and 1 attended the in-person visit only.
• At the in-person visits, children were examined for atopic dermatitis and underwent skin prick tests for food allergens (egg, milk, peanut) and airborne allergens (house dust mite, dog, cat, tree mix, timothy grass). Their stool and blood samples were also collected at these visits.
• Parents completed questionnaires on their child's environmental exposures, allergy and respiratory outcomes, medicines, and contact with health services.

TAKEAWAY

• The proportion of children sensitized to airborne allergens climbed from 8.9% at age 2 to 24% at age 5 (P < .001). Sensitization to house dust mite was most frequent (n = 33), followed by grass pollen (n = 25); 13% of children were sensitized to several allergens.
• Children sensitized to airborne allergens were substantially more likely to have symptoms of allergic rhinitis at age 5, and the risk was greatest among those sensitized to several allergens.
• The prevalence of atopic dermatitis fell from 21.3% at age 2 to 10.4% at age 5 (P < .01); of the 19 children with active disease at age 5, 18 had mild disease and none had severe disease. Food allergy was uncommon at age 5, and no child was allergic to milk or eggs.
• The prevalence of wheeze reported by parents remained stable between ages 2 and 5 and was strongly linked to asthma diagnosed by a doctor (P < .001).

IN PRACTICE

"We propose that lockdown-associated early-life environmental and lifestyle changes including higher breastfeeding rates, lower antibiotic exposure and early allergenic food introduction…may have altered early risk for food allergy, a benefit that persisted to 5 years, while the broader evolution of allergic disease remained consistent with recognised age-related trajectories," the authors wrote.

SOURCE

Jonathan O'B Hourihane, with the Paediatrics and Child Health, Royal College of Surgeons, Dublin, Ireland, was the corresponding author of the study, which was published online on September 16 in Pediatric Allergy and Immunology.

LIMITATIONS

The study had small numbers of children evaluated for some outcomes, including food allergy and doctor-diagnosed asthma, which limited its statistical power. Asthma at age 5 relied on parents reporting a doctor's diagnosis and may have covered a mix of conditions that were still taking shape. Most families came from socioeconomically advantaged backgrounds, which may have limited the generalizability of the findings.

DISCLOSURES

The study was supported by the Research Ireland Frontiers for the Future Programme. The authors reported having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.