Regional Patterns of Mite Sensitization in Atopic Dogs from Portugal: A Preliminary Study.

Abstract

Introduction and Objectives: Canine atopic dermatitis (cAD) is a chronic inflammatory skin disease influenced by genetic and environmental factors. Allergen-specific immunotherapy (ASIT) is a key treatment, but its efficacy relies on accurate allergen identification. Sensitization profiles are assessed using intradermal tests (IDT) and/or serum allergen-specific IgE (sIgE). Given regional variations in allergen prevalence, this study compared mite sensitization patterns in atopic dogs from two regions in Portugal and assessed IDT-IgE agreement. Materials and Methods: Thirty-four atopic dogs were included: 15 from the Interior South and 19 from the Central-South Coastal region. Diagnosis followed international guidelines, incorporating clinical assessment, exclusion of other pruritic diseases, and allergen testing. IDT was performed using commercial extracts of common environmental allergens, and sIgE levels were measured in a subset of dogs. Regional comparisons were analyzed using Fisher’s exact test, and IDT-IgE concordance was evaluated. Results: Significant regional differences in IDT results were observed for Dermatophagoides farinae (p=0.017) and Acarus siro (p=0.017), with higher sensitization rates in the Coastal region. No significant differences were found for Dermatophagoides pteronyssinus, Tyrophagus putrescentiae, or Lepidoglyphus destructor. IDT and sIgE results showed poor correlation, with some dogs testing negative for all sIgE allergens but positive on IDT. At least 2 of the 3 dogs in this category showed good initial responses to ASIT. Conclusions: These findings reinforce the relevance of IDT in allergen selection, particularly in cases with negative IgE results. The discrepancies suggest that sensitization may not always be reflected in circulating sIgE. A combined approach to allergy testing and region-specific panels may improve ASIT success. Despite a limited sample, these findings provide insights into mite sensitization in atopic dogs. Larger studies are needed to confirm these results and to further explore environmental influence on sensitization.