Olfactory and gustatory disorders associated with SARS-CoV-2 infection in children and adults: a topic review

This paper is aimed at comprehensively reviewing olfactory and gustatory disorders caused by SARS-CoV-2 in children and adults. An electronic and manual search was done on three databases: MEDLINE, Embase, and Web of Science. Inclusion criteria included publications written in English, involving humans in the age range of 0 to 99 years that were captured by a controlled vocabulary of thesaurus terms. Olfactory and gustatory disorders rates in COVID-19 ranged from 22% to 71.9% in adults and 16.6% to 25.8% in children. Olfactory and gustatory disorders might appear as the first symptom, and in adults might even be the only symptom (4.8% to 10%). Anosmia is the most common olfactory disorder and hypogeusia is the most common gustatory disorder. In 33% to 89% of cases, olfactory and gustatory disorders resolve spontaneously within a few weeks, coinciding with the resolution of other COVID-19 symptoms, both in adults and children. However, in some patients, olfactory and gustatory disorders persist beyond the resolution of other symptoms. Notably, children generally experience a swifter and more favorable recovery compared to adults. The precise pathogenesis underlying olfactory and gustatory disorders in the context of COVID-19 remains unclear and is likely multifactorial. Presently, no established treatment protocol exists for olfactory and gustatory disorders and current treatments reviewed lack robust evidence and are not readily available for clinical use. Olfactory training represents the only therapy currently recommended by international authorities. Pediatric practitioners and general dental practitioners should be aware of olfactory and gustatory disorders in both pediatric and adult populations, including their biologic mechanisms, treatment options, and recovery rates.