LAUSR

Postviral olfactory loss is the second leading cause of loss of sense of smell (anosmia), accounting for up to 40% of adult cases, mostly middle-aged or older women. Influenza or common cold viruses, including coronavirus disease 2019 (COVID-19), account for 12% (10%–15%) of individuals with anosmia. Recently, anosmia/hyposmia (the reduced ability to smell and to detect odors) has been reported as a major presenting symptom in patients with COVID-19 in the absence of other typical symptoms. For this article, we compiled information available in the literature and social media, aswell as the opinions of first-line healthcare providers who visited COVID-19 patients. A significant increase in anosmia has been observed in patients with COVID-19, in particular younger (younger than 40 years) healthcareworkers, presenting with isolated anosmia in northern Italy, Spain, France, Germany, the United Kingdom, the United States, Iran, and the Netherlands (P < 0.001). Because these individuals do not meet the criteria for COVID-19 testing or self-isolation, they as hidden carriers have induced widespread infection. Higher rates of COVID-19 infection have been reported in ear, nose, and throat (ENT) specialists who have performed upper airway procedures and examinations and in ophthalmologists in China, Italy, and Iran as compared with other healthcare workers. In a study of 2428 patients with COVID-19, 17% reported anosmia as their only symptom. Metra reported anosmia or dysgeusia (altered or impaired sense of taste) in the spouses of approximately 700 confirmed cases of COVID-19 infection in Italy. Mao et al detected hyposmia in 5.1% of hospitalized patients with COVID-19 in Wuhan, China. Approximately 1 in 3 (30% of 2000) cases with a positive COVID-19 test in South Korea and more than 2 in 3 confirmed COVID-19 cases in Germany presented only with anosmia. Hendrik Streeck, a German virologist who interviewed patients with coronavirus, explained that at least two-thirds of