Evaluation of Olfactory Disorders in Patients with Asthma

Background: Olfactory dysfunction is a common but under-diagnosed complaint, and there is a lack of studies evaluating the direct correlation between asthma and olfactory disorders. Objectives: To evaluate the presence of olfactory disorders in patients with asthma. Methods: Ninety-three patients with asthma aged ≥ 18 years were selected at the ProAR Clinic in Salvador, Brazil, between March 2019 and February 2020. All the patients underwent the University of Pennsylvania Smell Identification Test (UPSIT) and otorhinolaryngological/clinical evaluation. We analyzed the correlation between the classification of olfactory disorders and clinical variables of asthma. Results: Among the 93 enrolled asthmatic patients (63 had moderate to severe asthma and 30 had mild asthma), 89 (95.7%) were diagnosed with olfactory disorders, and four (4.3 %) had normosmia. Individuals with moderate to severe hyposmia or anosmia were older (56.5 years), while individuals with normosmia or mild hyposmia were younger (49.4 years) (p=0.029). Sixty-seven patients (72%) were diagnosed with chronic rhinosinusitis (CRS), but only 5.9% had nasal polyps. No statistically significant differences were found in the analysis of association between CRS and olfactory disorders. None of the patients with anosmia met the criteria for allergic rhinitis; however, all individuals with normosmia met the criteria for allergic rhinitis (p=0.035). We found that 86.9% of asthmatic patients with moderate to severe hyposmia or anosmia had used oral steroids in the previous year or injectable steroids in the last 6 months. Among individuals with normosmia or mild hyposmia, 64.5% had used oral or injectable corticosteroids during the same period (p=0.012). Fourteen patients in this study were not diagnosed with allergic rhinitis or CRS. The UPSIT demonstrated that all patients with no apparent nasal diseases had olfactory disorders. Conclusion: Olfactory disorders are common in asthmatic patients.