Characteristics of smell and taste disorders depending on etiology: a retrospective study

PURPOSE: This study investigates the impact of etiology on the epidemiologic profile, disease severity, type of treatment and therapy outcome in smell and taste disorders.

METHODS: This is a retrospective analysis of 270 patients that presented with a smell or taste disorder in a specialized, tertiary care center. An established questionnaire was used to collect data from patients and physicians. Olfactometry was performed with the Sniffin' Sticks test kit, while gustometry was performed by taste strips.

RESULTS: Post-traumatic etiology was associated with young age (median 46 years) and male sex, and showed the most severe degrees of smell loss compared to other etiologies (64.3% anosmia). Postinfectious causes occurred more frequently in females (77.3%) and correlated with a history of pharyngeal surgery, suggesting a vulnerability for virally mediated sensory dysfunction following adenoid/tonsil removal. Parosmia also correlated with both postinfectious etiology (62.5%) and female sex. In sinunasal etiology, the presence of nasal polyps worsened the overall olfactory test score by approximately 50%. In particular, smell threshold and discrimination were reduced, while smell identification was not significantly impacted by nasal polyp obstruction. Sinunasal dysfunction was the only etiology to show significant improvement after therapy (73.9% improved). Finally, we could establish good correlations between the subjective impairment and objective dysfunction for each sensory modality.

CONCLUSION: Each etiology of chemosensory dysfunction shows particular distributions of variables like sex, age, comorbidities and operations, disease severity, sensory threshold, discrimination and identification. This paper offers a detailed account of the correlations between the cause and the characteristics of smell and taste loss.