Background: Studies on the prevalence of Atopic Dermatitis (AD) for the adolescent cohort in general-based large populations are scarce worldwide. We performed a retrospective population-based observational cohort study of 76,665 adolescent patients diagnosed with AD in Catalonia (Spain). We study the prevalence of AD by age, gender, disease severity, comorbidities, and serum total Immunoglobin E (tIgE) and appropriate medical treatment (AMT) for the Catalan population. Methods: Adolescent individuals (12-17y) diagnosed with AD by medical records at different health care levels (primary, hospital, emergency) from the Catalan Health System (CHS) were included. Statistical analyses evaluated sociodemographic characteristics, prevalence, comorbidities, serum tIgE and AMT. Results: The overall diagnosed AD prevalence in the adolescent Catalan population (76,665) was 16.9%, being higher for the non-severe (16.7%) than for the severe (0.2%) populations. Topical corticosteroids were the most prescribed drug (49.5%), and the use of all prescribed treatments was higher in severe AD patients, especially systemic corticosteroids (49.7%) and immunosuppressants (45.4%). AD patients had, on average, a serum tIgE of 163.6 KU/L, which was higher for the severe than the non-severe disease (155.5 KU/L vs 101.9 KU/L, respectively). Allergic rhinitis (15.0%) and asthma (13.5%) were among the most frequent comorbid respiratory and allergy diseases. Conclusions: This is the first Spanish study reporting the overall diagnosed prevalence for a large-scale adolescent (12 to 17 years old) cohort from Catalonia. It provides new and robust evidence of AD’s prevalence and related characteristics in this region.

Background. Chronic rhinosinusitis with nasal polyps (CRSwNP), characterized by partial (hyposmia) or total (anosmia) loss of smell, is commonly associated with asthma and/or nonsteroidal anti-inflammatory drug-exacerbated respiratory disease (N-ERD), worsens disease severity and quality of life. The objective of this study was to determine whether, in real-life conditions, biological treatments prescribed for severe asthma can improve olfaction in patients with CRSwNP. A further objective was to compare smell improvement in N-ERD and non-N-ERD subgroups. Methods. A multicenter, non-interventional, retrospective, observational study was performed, including 206 patients with severe asthma undergoing biological treatment (omalizumab, mepolizumab, benralizumab, or reslizumab) with CRSwNP. Results. Improved olfaction was found after treatment with all monoclonal antibodies: omalizumab (35.8%), mepolizumab (35.4%), reslizumab (35.7%), and benralizumab (39.1%), with no differences between groups. Patients with atopy, greater use of short course systemic corticosteroids, and larger polyp size were more likely to experience improvement in smell. The proportion of patients experiencing smell improvement was similar between the N-ERD (37%) and non-N-ERD (35.7%) groups. Conclusions. This is the first study to compare real-life improvement in sense of smell among patients undergoing long-term treatment with omalizumab, mepolizumab, reslizumab, or benralizumab for severe asthma and associated CRSwNP. Approximately 4 out of 10 patients reported a subjective improvement in sense of smell (with non-significant differences between biologic drugs). No differences were found in smell improvement between the N-ERD and non-N-ERD group.