LP is an inflammatory dermatosis involving the skin and/or mucous membranes, of unknown etiology mediated by T lymphocytes. It can be associated with numerous triggers, such as medications, infections (such as Hepatitis C), and vaccines [
2]. Moreover, among the latter, the vaccines most frequently associated in the literature with LP are those for influenza and herpes zoster [
3]. There are currently few cases in the literature reporting a relationship between COVID-19 vaccination and the occurrence of lichen planus, and most were associated with the Pfizer vaccine or following the administration of vector-based COVID-19 vaccine (Ad26.COV2.S) [
4‐
8]. This is one of the first cases associated with the Moderna vaccine. McMahon et al. [
9] performed a registry-based study where they discussed the occurrence of vaccine-related eruption of papules and plaques (V-REPP) after COVID-19 vaccination. Among these skin manifestations, lichen planus was reported in four cases, three of which were related to the Pfizer vaccine and one to the Moderna vaccine. The physiopathological mechanisms underlying the relationship between LP and vaccination for COVID-19 are still poorly understood, however, it has been shown that after such vaccines there can be a stimulation of the immune response of T helper lymphocytes type 1 (Th1) [
10], leading to the stimulation of the production of interleukin (IL)-12, tumor necrosis factor (TNF)α, and interferon (IFN)γ, cytokines involved in the pathogenesis of LP [
11]. What emerges from the literature at present, is that COVID-19 vaccines can cause strong T-cell responses [
9‐
11]. The mechanism by which they might elicit immunostimulatory effects, including triggering T-cell-dependent disorders, requires further study. In fact, there are still few data in the literature that support a causal association between the pathophysiological mechanism just mentioned and the onset of LP.