Orofacial manifestations of COVID-19

COVID-19 is the viral pandemic that had created the medical emergency throughout the world especially with its severe form. This novel corona virus causes severe acute respiratory disease. The whole world had been under the search of an effective vaccine against this virus, which is a dif icult task but not impossible, as it has mutated continuously throughout the current year into different strains that makes the treatment protocol to be modi ied. The common way of transmission is through salivary droplets. The diagnosis made through the nasopharyngeal and oropharyngeal samples that mainly depends on saliva. Symptoms such as fever, headache, dry cough, sore throat, dyspnea, abdominal pain, vomiting, and diarrhea are also common [1].


Introduction
COVID-19 is the viral pandemic that had created the medical emergency throughout the world especially with its severe form. This novel corona virus causes severe acute respiratory disease. The whole world had been under the search of an effective vaccine against this virus, which is a dif icult task but not impossible, as it has mutated continuously throughout the current year into different strains that makes the treatment protocol to be modi ied. The common way of transmission is through salivary droplets. The diagnosis made through the nasopharyngeal and oropharyngeal samples that mainly depends on saliva. Symptoms such as fever, headache, dry cough, sore throat, dyspnea, abdominal pain, vomiting, and diarrhea are also common [1].

Mechanism
The SARS-COV-2 (severe acute respiratory syndrome-Corona virus) mainly acts on Angiotensin converting enzyme 2 (ACE 2) receptors which are commonly present in lung, liver, kidney, endothelia of dermal papillary vessels and epithelium of sweat glands etc [2,3]. The attachment between the virus and ACE 2 receptors begins the in lammatory reaction and produces prostaglandins, leukotrienes, cytokines and other in lammatory mediators [2][3][4], these in lammatory reactions causes melanogenesis and lead to hyper pigmentation.

Oral manifestations
With regard to oral mucosa, ACE2 receptors are commonly seen in dorsum of tongue and salivary glands [2]. Immuno-in lammatory processes have been associated with hyperpigmentation of melanin from the oral mucosa [3]. Symptoms such as mucositis, candidiasis, HSV-1 (Herpes simplex virus) infections, petechiae, xerostomia, geographic tongue, dysgeusia do occur. The oral manifestations can be appreciated through two ways. One may be direct sequelae of COVID-19 infection and the other may be secondary to suppression of human immune system or adverse effects of potential therapeutic drugs given for COVID-19 treatment [4,5].
Based on these two considerations, xerostomia and dysgeusia falls into irst category. As the salivary glands with ACE2 host cells are infected, the low and consistency of saliva becomes reduced and thick which may also paves the way for altered taste sensation [5,6]. The taste disorder is the early symptom in most of the patients with COVID-19 infection that can occur due to binding of SARS-COV-2 with salivary mucin and ACE2 receptors and affects the normal gustatory functions [5,[7][8][9]. Mucositis is also a very common symptom acquired as a result of thrombotic vasculopathy and vasculitis [10]. Salivary gland could be important source of COVID virus in saliva Positivity rate as high as 91.7% had also been reported [11,12].
In course of treatment, drugs such as azithromycin, hydrochloroquine sulphate, sulphamethoxazole and trimethoprim, enaxoparin sodium, meropenam, ceftriaxone sodium, which may cause adverse effects and reduces immunity that may lead to secondary conditions like geographic tongue, Melkerson-Rosenthal syndrome, postin lammatory pigmentation of gingiva, opportunistic infections such as oral thrush, Herpes Simplex Virus (HSV) infection, angina bullosa like lesions can also occur [2,8].

Discussion
Mucocutaneous lesions had been reported as part of MIS-C (Multisystem in lammatory syndrome in children [13]. COVID tongue in the form of discolouration, enlargement along with strange mouth ulcers had been reported in UK in early 2021 [14]. Rhino orbital mucormycosis had been reported as a severe fungal complication especially in older diabetic covid positive patient from India [15].
Within the available scienti ic literature on oral COVID manifestations, salivary diagnosis and oral symptoms are important predictors for this viral disease. Therapy for oral conditions is much more important not only during the COVID-19 treatment but also 1-2 weeks after the recovery from the disease [16]. Drugs such as luconazole, nystatin, acyclovir should be prescribed for oppurtunistic infections. Arti icial saliva can be suggested to manage xerostomia and oral hygiene measures such as use of chlorhexidine mouth washes, frequent change of tooth brush, and immersing the brush in 5% sodium hypochlorite solution for 30 minutes after every use should be advised [16,17].

Conclusion
In the current COVID-19 pandemic situation, dentists also have an important role to diagnose predisposing factors and treat oppurtunistic infections not only for this particular disease but also in limiting the spread of COVID infection by encouraging teleconsultation to identify proper patient selection for dental treatment and in implementing CDC (Centre for Disease Control-USA) guidelines and infection control protocol in day to day dental practice [1,18]. Teleconsulation is a mode of digital consolation enabled by way of various dedicated apps and through various hospital linked websites where the patient can ix up an online appointment with doctors for regular and extensive consultation. These digital sites are also enabled with links for uploading latest lab and radiographic reports of patients. Prescriptions are sent to patient's email and a copy is also available on the patient online account.