Clinical Characteristics of Lichen Planus Pigmentosus and Erythema Dyschromicum Perstans: Insights from a Retrospective Cohort

Background: Lichen planus pigmentosus (LPP) and erythema dyschromicum perstans (EDP) are pigmentary disorders that disproportionately affect individuals with skin of color. Diagnostic ambiguity often leads to misclassification as melasma or postinflammatory hyperpigmentation (PIH). Data remain limited regarding the demographic and clinical characteristics of affected patients. Case Presentation: We conducted a retrospective chart review of 300 patients with pigmentary disorders identified by ICD-10 codes L53.8, L81.9, L81.1, and L81.0 at an academic dermatology center. Extracted variables included demographics, medication history, laboratory values (vitamin D and thyroid levels), and histopathology. Multivariable logistic regression assessed factors associated with diagnosis and treatment. Discussion: Most patients with LPP/EDP were women with skin of color, and cases were rare among non-Hispanic White individuals. The cohort was predominantly middle-aged (40s–60s). Compared with melasma, LPP/EDP patients more frequently had trunk involvement and higher rates of hypertension and thyroid abnormalities. Hydrochlorothiazide use was more common but was not statistically significant after age adjustment. Coexisting scarring alopecia was observed in a subset of patients. Conclusion: LPP and EDP disproportionately affect women with richly pigmented skin and may be associated with specific comorbidities and medication exposures. Recognition of these patterns may improve diagnostic accuracy and support earlier identification and management.