Oral lichen planus post COVID-19 vaccination: report of two cases

Manifestations of сoronavirus disease 2019, caused by SARS-CoV-2 virus, are diverse and can vary from asymptomatic infection to respiratory failure needing intensive care. Vaccines against SARS‐CoV‐2 focusing on the spike glycoprotein have shown promise in diminishing the spread of Covid‐19. Adverse effects, however, are associated with every vaccination. Currently, there are literature reports of some cases of lichen planus eruption following COVID-19 vaccine injection. Oral lichen planus is a relatively common immune-mediated dermatologic disorder that can occur isolated or associated with cutaneous lichen planus. Postvaccination lichen planus has previously been reported in the literature as a rare adverse event following various vaccinations, especially hepatitis A and B, influenza, and varicella. The majority of patients presented with classic cutaneous lichen planus, although some reports highlighted primarily mucosal involvement. Herein we describe two rare cases of erosive-ulcerous oral lichen planus among SARS-CoV-2 vaccine recipients. The first is a case of a 67-year-old male who developed mucocutaneous lichen planus 5 days after administration of the single-dose of Ad26.COV2.S COVID-19 vaccine. In the second case, a 56-year-old female presented with reactivation of oral lichen planus after receiving a first dose of Pfizer COVID-19 vaccination 2 days earlier. The mechanism of the association between vaccines and lichen planus is not known, it is attributed to cell-mediated autoimmunity. Although there is currently no evidence of a causal relationship between SARS-CoV-2 vaccination and lichen planus, these clinical observations suggest that the COVID-19 vaccine is a possible key initiating event leading to the development or recurrence of this disease.