D2.294 - Clinical Characteristics of Food-Allergic Children with Peripheral Blood Hypereosinophilia

Food allergies are common immune-mediated disorders in childhood and may present with diverse IgE- and non-IgE–mediated clinical phenotypes. Eosinophils play a key role in type 2 immune responses, yet the clinical relevance and prognostic value of hypereosinophilia in children with food allergy remain unclear. This study aimed to evaluate the demographic, clinical, and laboratory characteristics of food-allergic children with hypereosinophilia and to investigate its association with clinical presentation and tolerance development.

This retrospective cohort study included children aged 0–18 years who were followed at a tertiary pediatric allergy clinic between October 2022 and December 2024 and had hypereosinophilia (absolute eosinophil count ≥1500/µL in two measurements at least one month apart). Clinical data, allergy phenotypes, skin prick test results, food-specific IgE levels, and follow-up outcomes were analyzed. Food allergy diagnosis was based on clinical history, allergy testing, and/or oral food challenge. Statistical analyses were performed to assess correlations between eosinophil levels and clinical variables.

Eighty patients were included (68.8% male), with a median age of 25 months. The most common clinical presentation was atopic dermatitis (52.5%), followed by urticaria (26.3%). Multiple food allergies were present in 75% of patients, most frequently to egg and cow’s milk. Median maximum eosinophil count was 2295/µL. Maximum eosinophil levels were not significantly associated with food allergy phenotype, age at onset, or tolerance development. However, a significant positive association was observed between family history of allergic disease and eosinophil levels (p<0.05). Egg white and egg yolk–specific IgE levels showed a significant positive correlation with eosinophil counts. During follow-up, eosinophil counts decreased in most patients. Lower final eosinophil levels were significantly associated with the development of clinical tolerance confirmed by oral food challenge (p<0.05).

In children with food allergy, hypereosinophilia appears to be a dynamic and mostly transient finding rather than a marker of specific clinical phenotypes. Decreasing eosinophil levels during follow-up may reflect resolution of allergic inflammation and development of tolerance. Monitoring eosinophil trends may provide a simple and useful prognostic indicator in the follow-up of pediatric food allergy.