This case report describes a woman infected by SARS-CoV-2 who had sudden and complete loss of the olfactory function without nasal obstruction.

Objective To assess the physiopathology of olfactory function loss (OFL) in patients with coronavirus disease 2019 (COVID-19), we evaluated the olfactory clefts (OC) on MRI during the early stage of the disease and 1 month later. Methods This was a prospective, monocentric, case-controlled study. Twenty severe acute respiratory syndrome coronavirus 2 (SARS-CoV2)–infected patients with OFL were included and compared to 20 age-matched healthy controls. All infected patients underwent olfactory function assessment and 3T MRI, performed both at the early stage of the disease and at the 1-month follow-up. Results At the early stage, SARS-CoV2–infected patients had a mean olfactory score of 2.8 ± 2.7 (range 0–8), and MRI displayed a complete obstruction of the OC in 19 of 20 patients. Controls had normal olfactory scores and no obstruction of the OC on MRI. At the 1 month follow-up, the olfactory score had improved to 8.3 ± 1.9 (range 4–10) in patients, and only 7 of 20 patients still had an obstruction of the OC. There was a correlation between olfactory score and obstruction of the OC (p = 0.004). Conclusion OFL in SARS-CoV2–infected patients is associated with a reversible obstruction of the OC.