Shifting patterns of mite sensitization in Spain and Portugal: real-world diagnostic and immunotherapy practices (MITE-WISE project)

Introduction Mite allergy sensitization profiles in Southern Europe are evolving. While Dermatophagoides spp . remain the most prevalent allergens associated with allergic rhinitis, asthma and atopic dermatitis, sensitization to Lepidoglyphus destructor and Blomia tropicalis has been increasingly reported in Iberian regions. Diagnostic and allergen immunotherapy (AIT) strategies may not reflect this shift. Methods Real-world, mixed-methods study guided by a Scientific Committee (SC) of allergists, comprising an online questionnaire completed by 215 allergists and semi-structured interviews with an Extended SC. Results Most specialists managed patients sensitized to Dermatophagoides spp. and L. destructor (97.7%) and to Dermatophagoides spp. and B. tropicalis (70.7%), reflecting allergist-reported clinical experience with these emerging mites. The eight interviewed experts perceived an increasing recognition of sensitization to L. destructor and B. tropicalis , particularly of B. tropicalis in the Canary Islands and along the Portuguese coast. Despite this, reported testing practices differed: 85.2% (179/210) reported always testing L. destructor , whereas 36.8% (56/152) reported routinely testing B. tropicalis , a descriptive difference that may reflect heterogeneous diagnostic practices. Among specialists who reported always testing the respective mite, 98.9% (177/179) of those testing L. destructor reported prescribing AIT targeting Dermatophagoides spp. and L. destructor , and 91.1% (51/56) of those testing B. tropicalis reported prescribing AIT targeting Dermatophagoides spp . and B. tropicalis , in patients with reported clinically relevant sensitization. All respondents reported a preference for subcutaneous AIT, and 98% of AIT prescribers reported using polymerized extract mixtures. Conclusion Among participating allergists, reported clinically relevant sensitization to Dermatophagoides spp . together with L. destructor or B. tropicalis was frequently followed by reported subcutaneous AIT within the subgroups that routinely tested the respective mite. Given the recruitment of AIT-experienced allergists, these proportions should not be generalized to all specialists. Testing was reported less frequently for B. tropicalis than for L. destructor . Whether region-specific inclusion of these mites in diagnostic protocols would improve diagnosis or treatment outcomes remains to be established in studies with objective confirmation of clinical relevance.