A case of lichen planus pigmentosus‐inversus after Oxford‐AstraZeneca COVID‐19 vaccine: cause or coincidence?

Lichen planus after COVID-19 infection and vaccination

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.

COVID-19 Vaccine-Induced Lichenoid Eruptions-Clinical and Histopathologic Spectrum in a Case Series of Fifteen Patients with Review of the Literature

Lichen planus is a distinctive mucocutaneous disease with well-established clinical and histopathologic criteria. Lichenoid eruptions closely resemble lichen planus and may sometimes be indistinguishable from it. Systemic agents previously associated have included medications, viral infections and vaccines. Sporadic case reports of lichen planus and lichenoid reactions associated with COVID-19 vaccines have recently emerged. Herein, we review the world literature (31 patients) and expand it with a case series of 15 patients who presented with vaccine-induced lichenoid eruption (V-ILE). The spectrum of clinical and histopathologic findings is discussed with emphasis on the subset whose lesions manifested in embryologic fusion lines termed lines of Blaschko. This rare Blaschkoid distribution appeared in seven of the 46 patients studied. Of interest, all seven were linked to the mRNA COVID-19 vaccines. We believe that all lichenoid eruptions should be approached with a heightened index of suspicion and patients should be specifically questioned with regards to their vaccination history. When diagnosed early in its course, V-ILE is easily treated and resolves quickly in almost all patients with or without hyperpigmentation. Additional investigative studies regarding its immunopathology and inflammatory signaling pathways may offer insight into other Th1-driven autoimmune phenomena related to COVID-19 vaccination.

Lichen planus pigmentosus post COVID-19-vaccination: A case report with literature review

Lichen planus (LP) is a T cell‐mediated chronic inflammatory disorder. Several clinical variants based on lesion morphology and localization are reported. LPP remains uncommon with an unknown etiology. Besides, some precipitating factors have been suggested in the literature including hepatitis C infection; restrictive underwear, localized friction, and sun exposure.^{(1, 2)} Herein, we present a case of new‐onset of LPP following the ChAdOx1 nCoV‐19 (Oxford‐AstraZeneca) vaccine. A literature review was also conducted to summarize the various cases of LP induced and/or trigged by Covid‐19 vaccine.

Extensive acquired macular hyperpigmentation in a teenager

A teenage girl with phototype IV skin presented with extensive gradually progressing asymptomatic macular hyperpigmentation not responding to topical steroids for several months. Histopathology showed foci of increased numbers of melanophages and melanin in the dermis.