The pathophysiologic mechanism might be the Th1 response that is elicited by the vaccines, which in turn leads to the elevation of interleukin‐2 (IL‐2), tumor necrosis factor‐α (TNF‐α), and interferon‐γ (IFN‐γ) levels, and therefore, lichen planus induction.25 This evidence concerns the gene IL2 and lichen planus.