Introduction
With the emergence of Coronavirus disease 2019 (COVID-19) outbreak on
December 20191, many researches have been published
about its transmission, diagnosis, clinical presentation and management.
Its presentation varies widely from mild to severe symptoms including
severs pneumonia. Though the main reported COVID-19 symptoms include
fever, headache, gastrointestinal symptoms, and respiratory
symptoms.2 Upper respiratory symptoms where not
uncommon such as sore throat, rhinorrhea, complete or partial loss of
smell (olfactory dysfunction-OD).3 Post viral
Olfactory dysfunction (PVOD) Is caused by different viruses including
Rhinoviruses, coronaviruses, parainfluenza viruses, and Epstein‐Barr
viruses.4 Many preliminary reports have suggested that
smell and taste loss are potential early symptom or subclinical markers
of COVID‐19 infection. Several cross-sectional studies from many
countries such as Iran, United Kingdom, Italy, Spain, Germany, European
countries, France, and united states have been published about OD
prevalence in COVID-19 patients.5,6 The incidence of
OD in COVID-19 patients differs widely between these cross-sectional
studies. ranging from 33.9 to 68%.5
A study from Spain using a self-reported questionnaire only without a
validated olfactory test, found that the incidence rate of OD in
COVID-19 patients was significantly more than OD in influenza patients
(39.2% vs12.5%).7 Olfactory tests are categorized in
to 3 types: subjective, psychophysical, and electorophysiological
studies. Subjective testing can be performed through self-reporting
method or as a part of quality of life outcome questionnaire eg.
Sinonasal outcome test-22 (SNOT-22). Many tests have been utilized to
assess the olfaction function objectively. These are the psychophysical
tests which measure some or all the three olfactory parameters: the
threshold, discrimination and identification. While subjective and
psychophysical tests are used in most clinical and research, the
electrophysiological studies like electroencephalography (EEG) and
electro-olfactography (EOG) are having limited clinical use and mainly
performed for medicolegal issues.8
One observational study from Saudi Arabia, found that self- reported
loss of taste and smell was the most common presentation (47.5%.) in
mild symptomatic COVID-19 patients.9 Objective
(psychophysical test) has been available in few studies only, though it
is considered to be the gold standard for diagnosis of
OD.2,10,11 Moein et al reported that only 35% of
their subjects were aware about their smell problem before doing
objective test which indicate that self-reporting of the symptoms may be
not enough and the incidence rate of OD is much higher than reported by
the previous studies.10
This study aims to use Quick Smell Identification Test (Q-SIT) as
screening tool to assess the prevalence of olfactory dysfunction in
patients with confirmed COVID-19 infection in Qatif area, Eastern
province, Saudi Arabia.