Olfactory and gustatory dysfunctions as a clinical presentation of mild-to-moderate forms of the coronavirus disease (COVID-19): a multicenter European study

Abstract

Objective: To investigate the occurrence of olfactory and gustatory dysfunctions in patients with laboratory-confirmed COVID-19 infection.

Methods: Patients with laboratory-confirmed COVID-19 infection were recruited from 12 European hospitals. The following epidemiological and clinical outcomes have been studied: age, sex, ethnicity, comorbidities, and general and otolaryngological symptoms. Patients completed olfactory and gustatory questionnaires based on the smell and taste component of the National Health and Nutrition Examination Survey, and the short version of the Questionnaire of Olfactory Disorders-Negative Statements (sQOD-NS).

Results: A total of 417 mild-to-moderate COVID-19 patients completed the study (263 females). The most prevalent general symptoms consisted of cough, myalgia, and loss of appetite. Face pain and nasal obstruction were the most disease-related otolaryngological symptoms. 85.6% and 88.0% of patients reported olfactory and gustatory dysfunctions, respectively. There was a significant association between both disorders (p < 0.001). Olfactory dysfunction (OD) appeared before the other symptoms in 11.8% of cases. The sQO-NS scores were significantly lower in patients with anosmia compared with normosmic or hyposmic individuals (p = 0.001). Among the 18.2% of patients without nasal obstruction or rhinorrhea, 79.7% were hyposmic or anosmic. The early olfactory recovery rate was 44.0%. Females were significantly more affected by olfactory and gustatory dysfunctions than males (p = 0.001).

Conclusion: Olfactory and gustatory disorders are prevalent symptoms in European COVID-19 patients, who may not have nasal symptoms. The sudden anosmia or ageusia need to be recognized by the international scientific community as important symptoms of the COVID-19 infection.

Keywords: Anosmia; COVID; COVID-19; Coronavirus; Dysgeusia; ENT; Gustatory; Hyposmia; Infection; Loss; Olfaction; Olfactory; SARS-CoV-2; Smell; Taste.

Fig. 1

Comorbidities of COVID-19 patients. The ordinate axis consists of percentages of patients with comorbidities in the cohort. Respiratory insufficiency consists of COPD, emphysema, fibrosis, or other chronic disease associated with a respiratory insufficiency. Neurological diseases include Parkinson disease, myasthenia, multiple sclerosis, and all degenerative diseases. COPD chronic obstructive pulmonary disease, CRS chronic rhinosinusitis, GERD gastroesophageal reflux disease

Fig. 2

General symptoms associated with COVID-19 infection. The ordinate axis consists of percentages of patients with such symptoms associated with the infection

Fig. 3

Pattern of recovery time for patients with olfactory dysfunction. The ordinate axis consists of percentages of patients. The patients with hyposmia or anosmia had the following recovery times a 1–4 days (33.0%), 5–8 days (39.6%), 9–14 days (24.2%), and more than 15 days (3.3%). The patients with anosmia had the following recovery times b 1–4 days (20.3%), 5–8 days (47.5%), 9–14 days (28.8%), and more than 15 days (3.4%)

Fig. 4

Therapeutic strategies for COVID-19 infection (a) and olfactory dysfunction (b)