Lichen planus autoimmune comorbidities: A retrospective case-control study

PURPOSE: To assess whether patients with lichen planus (LP) show increased prevalence and odds of autoimmune and viral comorbidities compared with matched controls using real-world data. METHODS: We analyzed TriNetX Linked Network electronic health records and claims data from 2016 to 2024 (more than 112 million patients). LP was defined by at least 2 International Classification of Diseases, Tenth Revision, Clinical Modification codes (excluding drug-induced variants) and matched 1:1 to controls on age, sex, and race. We calculated odds ratios (ORs), 95% confidence intervals, prevalence, and absolute risk differences (ARDs). RESULTS: The matched cohort included 43 458 LP and control patients (mean age, 53.8 years; 64.4% female). LP was associated with higher prevalence of autoimmune conditions, including psoriasis (6.59% versus 2.54%; ARD, 4.05%; OR, 2.71), lupus erythematosus (2.87% versus 1.13%; ARD, 1.74%; OR, 2.58), and autoimmune thyroiditis (3.09% versus 1.61%; ARD, 1.48%; OR, 1.95). Associations were also seen for Sjögren syndrome, alopecia areata, localized scleroderma, and vitiligo. Hepatitis C virus was more common in LP (2.95% versus 2.03%; ARD, 0.92%) but with a lower OR (1.47). CONCLUSION: LP was associated with substantially higher odds and prevalence of several autoimmune comorbidities, exceeding those for viral infections such as hepatitis C. These findings inform LP pathogenesis and comorbidity patterns but do not support changes to clinical management.