IgE ‐Binding Components in Fungi and Parasites: From Infection Severity to Allergy and Allergy Protection: An EAACI Position Paper

Human exposure to fungi and parasites (helminths, protozoa and ticks) can lead to the development and/or exacerbation of allergic/atopic diseases due to the production of IgE antibodies to components from these organisms. However, some of these IgE‐binding components are not currently listed in the official Allergen Nomenclature Database of the World Health Organization/International Union of Immunological Societies (WHO/IUIS) Allergen Nomenclature Sub‐Committee. The aim of the Task Force (TF) BACALL (including members from this Sub‐Committee and four additional groups/committees) was to identify in the literature (PubMed up to October 2025) potential allergens from fungi and parasites and their reported clinical relevance, for possible future inclusion in the WHO/IUIS Allergen Nomenclature Database according to Sub‐Committee criteria. Forty‐nine IgE‐binding proteins from fungi and parasites were identified as potential allergen candidates. The IgE‐binding oligosaccharide α‐Gal was excluded because it is not proteinic, although it is associated with allergic reactions and anaphylaxis. Exposure to helminths outside the context of infection, such as ingestion of Anisakis ‐infected fish or vaccination against hookworms, can also elicit allergic reactions. The TF recommends that non‐conventional routes of exposure be considered in the identification of new allergens, and that future studies assess the clinical relevance of new allergens identified by the TF in larger populations.