Introduction:
Since the onset of the coronavirus disease 2019 (COVID-19) pandemic in
Europe, many otolaryngologists have reported patients with a sudden loss
of smell.1,2 Olfactory dysfunction is rapidly becoming
a key symptom of COVID-19, with more than 66% of patients in Europe and
U.S reporting some degree of hyposmia.1,3-6 The loss
of smell has been reported to occur before (11.8%), after (65.4%) or
at the same time (22.8%) as the onset of other general or
otolaryngological symptoms.1 Knowledge around the
relationship between olfactory dysfunction and COVID-19 is rapidly
evolving. Recently, Yan et al . shown that anosmia seems to be
associated with a milder clinical course in patients with
COVID-19.6 Moein et al . suggested that 98% of
60 Iranian COVID-19 patients exhibited some olfactory dysfunction on
objective testing; only 35% of these patients were aware of
hyposmia/anosmia before testing.7 The nuances around
olfaction in COVID-19 appear to be associated with different clinical
parameters than other symptoms, and, consequently, warrant further
investigation.
The objective of this study was to investigate the olfactory dysfunction
of COVID-19 patients with subjective validated patient-reported outcome
questionnaires and objective psychophysical testing.