Lichen planus after COVID-19 infection and vaccination

Abstract

Lichen planus (LP) is an inflammatory disorder believed to result from CD8 + cytotoxic T -cell (CTL)-mediated autoimmune reactions against basal keratinocytes. We present a review of LP following COVID-19 infection and vaccination. Literature searches were conducted on PubMed and Google Scholar from 2019 to 7/2022. 36 articles were selected based on subject relevance, and references within articles were also screened. 39 cases of post-vaccination LP and 6 cases of post-infection LP were found among case reports and case series. 152 cases of post-vaccination LP and 12 cases of post-infection LP were found in retrospective and prospective studies. LP is a rare complication of COVID-19 infection and vaccination that may be mediated by overstimulation of T -cell responses and proinflammatory cytokine production. However, it does not represent a limitation against COVID-19 vaccination, and the benefits of vaccination considerably outweigh the risks.

Characteristics, comorbidities, and treatment practices of lichen planus in Northern Finland: A register‐based study among 619 subjects

“…However, HCV was not a frequent comorbidity in the current study, as it was present in only four patients. Recently, many case studies have reported an onset of LP after COVID‐19 infection or vaccination 21 . Nevertheless, a general health, comorbidities and immunological status (i.e., factors having an influence on the immune system) of these people have often been insufficiently described, 22 and thus, more studies are needed to confirm the real relationship between LP and COVID‐19 infection or vaccination.…”

Cutaneous reactions secondary to COVID‐19 vaccination

“…Another hypothesis is that the ACE2 receptors on epidermal cells that act as a target for both infection and vaccination are in abundance in the skin and oral mucosa, driving Th1 recruitment and activating the autoimmune cascade that results in lichen planus. Messenger RNA COVID‐19 vaccines are more commonly associated with lichen planus 10,24 …”

Response to Commentary on Lichen planus after COVID-19 infection and vaccination

“…However, we acknowledge that comorbidities may remain a confounding factor. In the Discussion section of our review, we also mentioned that immunocompromising comorbidities such as hypertension, diabetes, vitamin D deficiency, and vitiligo may be risk factors that increase susceptibility to LP after COVID-19 infection and vaccination [1]. We further invite the authors to review the clinical generalizability of their reference when discussing comorbidities for lichen planus, as their reference is a case report on dengue after COVID-19 vaccination [2].…”

“…The authors raised the concern that a layperson's internet post may not guarantee a precise diagnosis. We would like to clarify that all of the references cited in our review were from peer-reviewed studies in which diagnoses of lichen planus were made by qualified healthcare providers through clinical or histopathological findings [1].…”

“…The authors also discussed how comorbidities may complicate the clinical relationship between lichen planus and COVID-19 infection and vaccination. In the vast majority of our references, the authors of these peer-reviewed studies strived to account for patients' comorbidities based on their documented medical histories [1]. After reviewing comorbidities, lichen planus onset as an adverse reaction to COVID-19 vaccination or sequelae to COVID-19 infection remained a likely possibility based on the close temporal relationship between these clinical events.…”