D3.215 - Shifting patterns of mite sensitization in Southern Europe: Real-World diagnostic and immunotherapy practices in Spain and Portugal (MITE-WISE Project)

House dust mite (HDM) allergy patterns in Southern Europe are shifting. Dermatophagoides spp. are the most prevalent HDM allergens in Europe, associated with allergic rhinitis, asthma, and atopic dermatitis​​. While Dermatophagoides spp. remain the dominant allergens, emerging sensitizations to Lepidoglyphus destructor (L. destructor) and Blomia tropicalis (B. tropicalis) are increasingly reported in Spain and Portugal, likely driven by climate change and population mobility. However, current diagnostic algorithms and allergen immunotherapy (AIT) strategies may not fully reflect this evolving landscape, potentially leading to underdiagnosis and suboptimal etiological treatment.

The objective of this project was to describe diagnostic and AIT practices for patients co-sensitised to Dermatophagoides spp. and L. destructor or B. tropicalis in Spain and Portugal

MITE-WISE was a real‑world, mixed‑methods study guided by a Scientific Committee (SC) of recognized allergologists, comprising an online questionnaire completed by 222 allergologists (Spain, n=200; Portugal, n=22) and subsequent semi-structured interviews (n=8) conducted with an Extended SC of regional experts in mite allergy and AIT.  

The majority of specialists reported treating patients co-sensitised to D. pteronyssinus and L. destructor (97.6%), and to D. pteronyssinus and B. tropicalis (68.9%), confirming the clinical relevance of emerging mites. Experts highlighted a progressive increase in L. destructor and B. tropicalis sensitisation, with relevance of the latter in the Canary Islands and Portuguese coast. Despite this, systematic testing differed significantly: 85.7% of specialists always test for L. destructor, whereas only 36.6% routinely test for B. tropicalis, suggesting potential regional underdiagnosis.

When co-sensitisation is confirmed, treatment decisions are highly concordant: 98.9% of specialists prescribe AIT targeting Dermatophagoides spp. and L. destructor, while 91.1% do so for Dermatophagoides spp. and B. tropicalis. Furthermore, all participants prefer subcutaneous AIT and widely use polymerized extract mixtures, considering mixtures of Dermatophagoides spp. with B. tropicalis (98%) or with L. destructor (97.8%). 

In spanish and portuguese practice, confirmed co-sensitisation to Dermatophagoides spp. and L. destructor or B. tropicalis usually leads to subcutaneous AIT with polymerized mixtures, supporting their role as a cornerstone in the management of HDM allergy. Therefore, it is crucial to include emerging mites in region-specific diagnostic protocols and guidelines to optimize patient treatment.