Sir, I read with interest the emerging media reports of a possible association between geographic tongue (GT) and SARS-CoV-2 infection, recently coined as 'COVID tongue'. These reports have been identified through the ZOE COVID-19 Symptom Study app, where participants submit symptom reports on a daily basis. Professor Spector, the study's lead researcher from King's College London, has reported a number of user submissions that seem to be consistent with GT, but to date there are only two communications in the literature reporting it as part of COVID-19 illness.1,2
GT, otherwise known as Erythema migrans, is not an uncommon finding on the oral medicine clinic. Adult incidence is around 1-2%. Typically, it presents with irregular areas of depapillation on the dorsal aspect of the tongue. These areas may change in size, shape and position, much like continental drift, as its name suggests. It affects both males and females and may be seen at any age.
While some elements of the media have called for COVID tongue to be added to the list of COVID-19 symptoms, its diagnostic value remains unknown and should be treated with caution. Such findings may represent a pre-existing GT.
However, as dental professionals, we must also be receptive to these developments. If a GT is of recent onset, could it signify COVID-19? Possibly. There is some evidence to suggest that GT might be associated with elevated levels of the inflammatory cytokine interleukin-6 (IL-6),3 the same cytokine that is upregulated in severe COVID-19 disease.4 It is also worthwhile remembering that angiotensin-converting enzyme 2 (ACE2) receptor expression is higher in the tongue relative to other oral tissues.5 ACE2 receptors are the entry point of the SARS-CoV-2 virus.
Further research is necessary, but as media interest may generate some concern among our patients, we must keep abreast of these developments and remain vigilant.
References
- 1.Rodríguez M D, Romera A J, Villarroel M. Oral manifestations associated with COVID-19. Oral Dis 2020; DOI: 10.1111/odi.13555. [DOI] [PMC free article] [PubMed]
- 2.dos Santos J A, Normando A G C, da Silva R L C et al. Oral mucosal lesions in a COVID-19 patient: new signs or secondary manifestations? Int J Infect Dis 2020; 97: 326-328. [DOI] [PMC free article] [PubMed]
- 3.Alikhani M, Khalighinejad N, Ghalaiani P, Khaleghi M A, Askari E, Gorsky M. Immunologic and psychologic parameters associated with geographic tongue. Oral Surg Oral Med Oral Pathol Oral Radiol 2014; 118: 68-71. [DOI] [PubMed]
- 4.Leisman D E, Ronner L, Pinotti R et al. Cytokine elevation in severe and critical COVID-19: a rapid systematic review, meta-analysis, and comparison with other inflammatory syndromes. Lancet Respir Med 2020; 8: 1233-1244. [DOI] [PMC free article] [PubMed]
- 5.Xu H, Zhong L, Deng J et al. High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa. Int J Oral Sci 2020; 12: 8. [DOI] [PMC free article] [PubMed]