Phenotypes of Food Allergies in Patients with Atopic Dermatitis Aged Under 24 Months: A Multicenter Study.

Background: Atopic dermatitis (AD) and food allergy (FA) are common allergic diseases in early childhood. AD may be concomitant with FA, particularly in young children. Although studies report the prevalence of FA in children with AD, there is insufficient data regarding different phenotypes of FA. Objective: The aim of our research was to determine the prevalence and clinical predictors of different phenotypes of concomitant FA in children with AD. Methods: This cross-sectional multicenter study included patients younger than 24 months old diagnosed with AD, recruited from 14 pediatric allergy centers. Patients were categorized into two groups using skin testing, allergen-specific IgE, and ultimately food challenge testing (FCT): those with FA and those without. Individuals with FA were classified into three distinct phenotypes: IgE-mediated, non-IgE-mediated, and concurrent IgE- and non-IgE-mediated. Results: The data of 530 children [59% male, median-age 7 months (IQR: 5-11)] were analyzed. IgE-mediated FA was found in 28.1% of participants, whereas 22.4% (n = 119/530) exhibited non-IgE-mediated FA. Concurrent IgE- and non-IgE-mediated FA was reported in 12.1% (n = 64/530) of patients. Cow's milk (69.6%) and egg-white (68.9%) were identified as the most prevalent allergens. Cow's milk was primarily responsible for non-IgE-mediated and egg-white for IgE-mediated FA. The most significant predictors of FA were severe AD and the presence of blood in stool with odds ratios of 8.25 (95% Cl: 3.04-22.39) and 10.04 (95% CI: 2.03-49.59), respectively (p < 0.01) (p < 0.005). Conclusions: The study's findings indicate that children with early-onset and mild-to-moderate AD deserve to be comprehensively assessed for FA symptoms. The most significant indicators of concomitant FA in AD patients were the presence of blood in stool and severe AD. It is important to consider that those who exhibit IgE-mediated FA may also have concurrent non-IgE-mediated FA. We underline that it is important to consider that children with AD who exhibit IgE-mediated FA may also have concurrent non-IgE-mediated FA. Addressing these symptoms may assist healthcare practitioners in clinical practice to improve the quality of care for AD patients having FA.