Background: The effect of leprosy on the sense of smell is not yet fully established. Studies that have relied only on patients' perceptions may have under- or over-estimated the change in smell perception. A validated and psychophysical method is necessary to avoid these errors in assessment.
Objectives: This study aimed to validate the existence of olfactory involvement in leprosy patients.
Methods: A cross-sectional, controlled study was conducted, in which individuals with leprosy (exposed individuals) and individuals without leprosy (control patients) were recruited. For each exposed individual, we selected two control patients. A total of 108 patients (72 control patients and 36 exposed individuals) with no history of infection with the new coronavirus (COVID-19) took the University of Pennsylvania Smell Identification Test (UPSIT).
Results: Most exposed individuals had olfactory dysfunction [n = 33, 91.7% (CI 95%: 77.5%-98.3%)] when compared with the control patients [n = 28, 38.9% (CI 95%: 27.6%-51.1%)], but only two (5.6%) had olfactory complaints. The olfactory function was significantly worse among exposed individuals [UPSIT leprosy = 25.2 (CI 95%: 23.1-27.3) when compared with the UPSIT control patients = 34.1 (CI 95%: 33.0-35.3); p<0.001]. The risk of olfactory loss was higher among the exposed individuals [OR: 19.5 (CI 95%: 5.18-105.70; p < 0.001)].
Conclusions: Olfactory dysfunction was highly prevalent among exposed individuals, although they had little or no self-knowledge of the disorder. The results show that it is important to assess the sense of smell in exposed individuals.
Copyright: © 2023 Kondo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.