key: cord-1055865-zqm5fl38 authors: Vinayachandran, Divya; Balasubramanian, SaravanaKarthikeyan title: Is gustatory impairment the first report of an oral manifestation in COVID‐19? date: 2020-05-18 journal: Oral Dis DOI: 10.1111/odi.13371 sha: 89b50fe3c7e27f546c0bfc3112130a6771793139 doc_id: 1055865 cord_uid: zqm5fl38 More recently, researchers Top of FormBottom of Formhave reported about the chemosensory alterations observed in patients with COVID-19 (Giacomelli et al., 2020). The findings on changes in olfactory and gustatory sensations are enlightening and probably one of the preliminary reports in this context and may have been overlooked earlier, since it is challenging to diagnose and also due to the gravity of the major symptoms, being dealt with. Dear Editor, More recently, researchers have reported about the chemosensory alterations observed in patients with COVID-19 (Giacomelli et al., 2020) . The findings on changes in olfactory and gustatory sensations are enlightening and probably one of the preliminary reports in this context and may have been overlooked earlier, since it is challenging to diagnose and also due to the gravity of the major symptoms, being dealt with. Disorders of the olfactory system have been implicated as the cause for 95% of the cases with taste disorders (Malaty & Malaty, 2013) . Patients frequently have difficulty in delineating between smell and taste disturbances. Therefore, in patients reporting with both olfactory and taste disturbances in COVID-19, the possibility of an underlying olfactory disturbance should be considered as the primary aetiology. The perceived taste impairment could be secondary to this, rather than any actual disturbances with the gustatory system. Whereas, the patients who reported only with dysgeusia and ageusia, in the absence of any olfactory disorders, have to be highlighted, since this could be the first report of any oral manifestation associated with COVID-19. The taste buds containing the taste receptors are widely distributed in the oral cavity but are mainly concentrated in the papilla present on the dorsum of the tongue (Matsuo, 2000) . This is of particular importance because the angiotensin-converting enzyme 2 (ACE2) receptor, to which the SARS-CoV-2 binds, in order to gain entry into the host cell, is highly expressed in the epithelial cells of especially the tongue, in comparison to the buccal or gingival tissues of the oral cavity (Xu et al., 2020) . Hence, this could be a possible reason for the taste disturbance, observed in COVID-19 patients. It was also suggested in a recent study that the Pennsylvanian smell identification test can be used for assessing olfactory disturbances in COVID-19 cases (Giacomelli et al., 2020) . Similarly, investigations like whole mouth test, spatial taste test (tongue mapping) can be employed to check taste disorders (Ambaldhage, Puttabuddi, Nunsavath, & Tummuru, 2014) . Additionally, these tests can help to localize the areas of impairment and threshold sensitivity to a particular taste. It is also well known that changes in the quantity and composition of saliva can contribute to taste disturbances (Matsuo, 2000) . It was earlier reported that ACE2 receptors in the epithelial cells of the salivary glands of rhesus macaques were an initial target for the SARS coronavirus (Liu et al., 2011) . Considering the phylogenetic similarity between SARS-CoV and SARS-CoV-2 (Zhou et al., 2020) , this can be a possible explanation for the gustatory disturbance in patients with COVID-19. Thus, the presence of xerostomia (hyposal- Taste disorders: A review Self-reported olfactory and taste disorders in SARS-CoV-2 patients: A cross sectional study Epithelial cells lining salivary gland ducts are early target cells of severe acute respiratory syndrome coronavirus infection in the upper respiratory tracts of rhesus macaques Smell and taste disorders in primary care Role of saliva in the maintenance of taste sensitivity High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa A pneumonia outbreak associated with a new coronavirus of probable bat origin