Introduction: Allergic diseases, particularly allergic rhinitis and asthma are highly prevalent among children and adolescents and frequently associated with sensitization to inhalant allergens. However, recent data on sensitization profiles in the Portuguese pediatric population are scarce, especially regarding regional and demographic variability. In this context, we aimed to characterize the clinical and allergen sensitization profiles of children and adolescents with allergic diseases in Portugal, through a multicenter approach.
Methods: We conducted a retrospective, cross-sectional study across 14 Portuguese hospitals between January 2021 and June 2023. Children and adolescents (< 18 years) with a clinical diagnosis of allergic diseases and at least one positive skin prick test to inhalant allergens were included. Demographic, clinical, and environmental data were collected from electronic medical records. Skin prick tests followed European Academy of Allergy & Clinical Immunology recommendations. Statistical analysis was performed using IBM® SPSS® Statistics version 29.
Results: A total of 3456 patients were included (60.5% male; median age 10 years). Allergic rhinitis (78.1%) and asthma (54.5%) were the most common diagnoses and 43.1% presented with both conditions. Sensitization was most frequent to Dermatophagoides pteronyssinus (84.3%) and Dermatophagoides farinae (74.3%), followed by Lepidoglyphus destructor (57.8%), grass pollens (60.4%), and Blomia tropicalis (23.5%). Polysensitization occurred in 58.4% of patients. Sensitization patterns varied with age. Geographic differences were noted: house dust mites sensitization predominated in coastal regions, whereas sensitization to pollens, molds, and animal epithelia was more frequent inland. Migrant children (14.2%) showed lower sensitization rates to most allergens, despite a comparable disease burden.
Conclusion: To the best of our knowledge, this is the first multicenter study to describe pediatric allergen sensitization patterns in Portugal. The high rates of polysensitization and the regional variability underscore the importance of tailored diagnostic strategies. Skin prick test remains a key tool in the initial assessment of allergic diseases.
Keywords: Allergens; Child; Hypersensitivity; Portugal; Skin Tests.