Objective olfactory evaluation of self-reported loss of smell in a case series of 86 COVID-19 patients

Objective To investigate olfactory dysfunction (OD) in patients with mild coronavirus disease 2019 (COVID-19) through patient-reported outcome questionnaires and objective psychophysical testing. Methods COVID-19 patients with self-reported sudden-onset OD were recruited. Epidemiological and clinical data were collected. Nasal complaints were evaluated with the sinonasal outcome-22. Subjective olfactory and gustatory status was evaluated with the National Health and Nutrition Examination Survey. Objective OD was evaluated using psychophysical tests. Results Eighty-six patients completed the study. The most common symptoms were fatigue (72.9%), headache (60.0%), nasal obstruction (58.6%), and postnasal drip (48.6%). Total loss of smell was self-reported by 61.4% of patients. Objective olfactory testings identified 41 anosmic (47.7%), 12 hyposmic (14.0%), and 33 normosmic (38.3%) patients. There was no correlation between the objective test results and subjective reports of nasal obstruction or postnasal drip. Conclusion A significant proportion of COVID-19 patients reporting OD do not have OD on objective testing.