Chemosensory disorders in Covid-19: Pathomechanisms and clinical relevance

Abstract

In this review article, current information on the frequency and relevance of chemosensory disorders in Covid-19 was recorded, assigned pathophysiologically and statements on prognostic significance were derived. The results are based on a comprehensive literature search of all literature on this topic and our own experience in the treatment of patients with smell and taste disorders since the beginning of the pandemic.Current study results indicate that clinically less affected Covid-19 patients without inpatient treatment and who do not require ventilation often have disorders of the chemosensory system. In young patients and women in particular, they seem to be an indicator of a favorable prognosis for the course of the disease. Smell disorders can appear early, as the sole symptom or together with other symptoms of Covid-19 disease. It has not yet been clarified whether ageusia can occur independently or whether it is also felt in the context of anosmia. In the pandemic, the new occurrence of anosmia without congestion / obstruction/runny nose is probably an expression of an infection with SARS-CoV-2 and should always give rise to quarantine and testing for SARS-CoV-2. The smell disorder in Covid-19 mostly seems to be temporary; It is not yet possible to conclusively assess whether there is usually a full restitution. The therapeutic approaches already established for other postviral olfactory disorders (e. g. olfactory training) are also used here.