Pharmacologic therapy of olfaction disroders induced by COVID-19 upper respiratory infection

ABSTRACT

Postviral olfactory disorder refers to the sensorineural olfactory loss caused by upper respiratory tract infections. With the increasing awareness of olfactory or gustatory dysfunction as a potential early symptom of coronavirus disease 2019, postviral olfactory disorder has been attracting much attention. Postviral olfactory disorder is the most common type of olfactory disorder, especially among women aged over 50 years. Systemic or topical corticosteroids have commonly been used for treating this disorder, but the mechanism of corticosteroid action is unclear. Other medical treatment options such as alpha-lipoic acids and caroverine that stimulate nerve growth factor expression or prevent glutamatergic neurotoxicity have also been used. Although these drugs have been found to be useful in the treatment of postviral olfactory disorder in previous studies, the efficacy has not been statistically proven through a meta-analysis. Recently, olfactory training has been introduced in the treatment strategy for postviral olfactory disorder. It is a safe option without side effects that can be used for treating olfactory disorders caused by upper respiratory tract infections. Further rigorous studies are needed to determine the efficacy of the combination of drug treatment and olfactory training.