TABLE 2.

Distinctive features of case series(n = 3) and case reports (n = 10) included in the systematic review

S. No.	Study Id	Study design	Sample (total no)	Age,Y, mean	Covid‐19 grade/Severity	Clinical signs and symptoms	Oral manifestations	Time of oral presentation	Diagnostic method of oral manifestations	Conclusion	Risk of bias
1	Tapia ROC etal, 2020, Mexico	Case series	4 (3 F, 1 M)	41 F, 51 F, 55 F, 42 M (mean age range‐47.2 ± 6.8.)	Non‐hospitalised (Case 1), hospitalised (Case 2), non‐hospitalised (Case 3), non‐hospitalised (Case 4)	Fever, myalgia, headache, dysphagia, hyposmia, nasal congestion	Angina bullosa hemorrhagica, vascular‐like purple macule on palatal mucosa, burning mouth, dysgeusia and erythematous macules	During COVID‐19 infection	Extraoral and intraoral physical examination	It is important to consider that oral mucosal lesions in COVID‐19 individuals could mimic others oral diseases, such as reactive, vascular and immunological disorders, being necessary to differentiate them to establish the correct diagnosis and clinical management in patients with SARS‐CoV‐2 infection.	Moderate
2	Fisher J et al, 2021, Boston, USA	Case report	1	21 Y, F	Non‐hospitalised	Fever, cough, dyspnoea, left sided facial and neck swelling	acute infectious parotitis, malocclusion due to inflammation surrounding muscles of mastication	During COVID‐19 infection	Physical extraoral and intraoral examination	Atypical presentations of COVID‐19 are being increasingly recognized. Emergency department clinicians must have a high suspicion for COVID‐19 among any patient presenting with infectious symptoms or viral‐associated illnesses and don available PPE accordingly for the initial evaluation.	Moderate
3	Lima MA et al, 2020, Brazil	Case series	8	Females were 7, Male‐1, Mean‐36 years	Non‐hospitalised	Mild respiratory and systemic COVID‐19 SYMPTOMS	Facial palsy	During COVID‐19 infection	Physical extraoral and intraoral examination	Peripheral facial palsy should be added to the spectrum of neurological manifestations associated with COVID‐19. Most patients had an uncomplicated course with good outcome, and SARS‐CoV‐2 RNA could not be detected in Cerebrospinal Fluid (CSF) of any patient.	Low
4	Ferreira ACAF et al, 2020, Brazil	Case report	1, M	39 Y	Hospitalised	Fatigue, diarrhoea, fever	Left facial herpes zoster with intraoral mucosal lesions, hypogeusia	During COVID‐19 infection	Physical extraoral and intraoral examination	The emergence of the latent infection by VZV under a rare presentation might illustrate the impact at least locally of COVID‐19, once retrograde reactivation of VZV was possibly induced in a young immunocompetent patient.	Low
5	Taslidere B et al, 2021, Turkey	Case report	1	51 Y, F	Hospitalised	Malaise, pneumonia	Hyperaemic, firm oedema in the right lower lip extending towards the jaw, right facial paralysis, fissured tongue, (Melkersson‐Rosenthal syndrome)	During COVID‐19 infection	Physical extraoral and intraoral examination	Activated mast cells also play a part in the pathogenesis of COVID‐19 infection, as they release cytokines in the lungs. COVID‐19 may be associated with which was not previously included in the aetiology of the disease.	Low
6	Figueiredo R et al, 2020, Portugal	Case report	1	35 years, F	Non‐hospitalised. (Admitted due to 39‐week pregnancy in gynaecology department)	Lagophthalmos, No other symptoms including fever, dyspnoea, cough, anosmia, ageusia	Bell's palsy showing involuntary drooling, left side labial commissure deviation	During COVID‐19 infection	Physical extraoral and intraoral examination	COVID‐19 may be a potential cause of peripheral facial paralysis.Neurological symptoms could be the first and only manifestation of the COVID‐19	Low
										Pregnant women have higher susceptibility for peripheral facial palsy and functional prognosis can be worse.
7	Lechien JR et al, 2020, Belgium	Case series	3	23/F, 31/F, 27/F	Non‐hospitalised	Anorexia, arthralgia, myalgia, fatigue, headache, nasal obstruction, rhinorrhoea, postnasal drip, sore throat, face pain, loss of smell and taste	Parotitis characterised by ear pain, retromandibular oedema, sticky saliva, pain during chewing	During COVID‐19 infection	Physical extraoral and intraoral examination	Parotid inflammation might be encountered in COVID‐19 patients and could be related to intraparotid lymphadenitis.	Low
8	Caamano DSJ and Beato RA, 2020, Spain	Case report	1	61/M	Non‐hospitalised	Fever, cough	Bilateral facial nerve palsy with unresponsive blink reflex on both eyes, Guillain‐Barré syndrome (GBS)	During COVID‐19 infection	Physical extraoral and intraoral examination	There is a clear emerging group of neurological manifestations during and after SARS‐CoV‐2 infection; some directly linked, others not so much.case is a highly probable GBS DP variant.	Low
9	Kammerer T et al, 2021, Germany	Case report	1 (M)	46Y	Hospitalised (ICU)	Fatigue, dry cough, fever, respiratory distress	Multiple sharply circumscribed ulcerations of the oral mucosa covered by yellow–grey membranes. Secondary herpetic gingivostomatitis	During COVID‐19 infection	Physical extraoral and intraoral examination	COVID‐19 infection and prolonged inpatient care were causal factors of stress induction and immunosuppression, leading to the distinct oral manifestations.	Low
10	Kitakawa D et al, 2020, Brazil	Case report	1	20 Y/F	Non‐hospitalised	Severe sore throat and headache	Lesions in the median lower lip semimucosa and severe pruritus, with a clinical course of 14 days, clinical diagnosis of herpes simplex infection.	During COVID‐19 infection	Physical extraoral and intraoral examination	Most of these cases could occur in patients who have experienced COVID‐19 infection	Low
11	Andrews E et al, 2020, USA	Case report	1	40 Y/F	Hospitalised (ICU)	Fevers, shortness of breath and diarrhoea, acute respiratory distress	Severe, persistent macroglossia following prone positioning as part of treatment for COVID‐19.	During COVID‐19 infection	Physical extraoral and intraoral examination	Patient's macroglossia was the result of a prolonged course of prone positioning for treatment of COVID‐19.	Low
12	Gil JM et al, 2021, Spain	Case report	1	65 Y/M	Non‐hospitalised	General malaise, arthromyalgia, dry cough, and low‐grade fever.	Paroxysmal lancinating pain in the right V1 region that lasted a few seconds and was triggered by a light touch of the skin at a specific point on the scalp. Diagnosed as trigeminal neuralgia.	During COVID‐19	Physical extraoral and intraoral examination	The new coronavirus SARS‐CoV‐2 is a possible aetiology of secondary Trigeminal neuralgia (TN). Nevertheless, more studies are needed to elucidate the neuropathology of this viral infection.	Low
13	Soares CD et al, 2020	Case report	23 Y/F	23 Y	Non‐hospitalised	Fever and dry cough 3 days prior to oral presentation	Vesiculobullous lesions in the lips with an erythematous halo	During COVID‐19	Physical extraoral and intraoral examination	This is the first report showing the SARS‐CoV‐2 spike protein in oral lesions of patients with COVID‐19.	Low

Abbreviation: PPE, personal protective equipment.