Monitoring of seasonal skin sensitivity to apple and IgE reactivity to birch pollen allergen Bet v 1 and apple allergen Mal d 1, in patients with birch pollen allergy

Birch pollen allergy is widespread globally and ranks among the leading allergic diseases in Russia. Cross-reactive food allergy, often observed in patients with birch pollen allergy, is an underestimated issue that exacerbates the course of pollinosis. The presence of cross-reactive food allergy significantly impacts the quality of life of patients with pollinosis. Unlike reactions to pollen, reactions to plant foods can occur year-round and may sometimes have severe, even life-threatening manifestations (e.g., angioedema of the lips and tongue, laryngeal edema, urticaria, anaphylaxis). In many patients, сross-reactive food allergy symptoms first appear during or immediately after the pollen season. According to existing scientific data, this may be due to an increase in the levels of specific immunoglobulin E during the flowering season, both to the causative pollen allergens and to cross-reacting food allergens. The article presents two clinical cases of development of oral allergy syndrome after consuming raw apple during the birch flowering season, demonstrating possible differences in the mechanisms of cross-reactive food allergy to apple in patients sensitized to birch pollen allergen. © 2025 Elsevier B.V., All rights reserved.