Riehl’s Melanosis in a Chinese Cohort: Frequent Association with Connective Tissue Diseases-Related Autoantibodies, but Without Systemic Manifestations

Introduction: Riehl’s melanosis (RM) has been recognized as pigmented contact dermatitis. Its pathogenesis remains unclear due to disease rarity and lack of in-depth investigation. A few sporadic case reports have indicated the presence of connective tissue diseases (CTDs)-related autoantibodies in RM, and even a possible association with CTDs, but whether this linkage is causal or coincidental is unknown. Objectives: To investigate the association between RM and CTDs-related autoantibody abnormalities and assess whether RM patients develop systemic symptoms related to CTDs. Methods: A single-center retrospective study of patients diagnosed with RM evaluating clinical and pathologic characteristics, CTDs-related autoantibody results, and follow-up for systemic symptoms related to CTDs. Results: Totally 183 patients were included (mean age 44.5 ± 11.2 years; female: male ratio 9.1:1), most were middle-aged women (30-50 years). Of 125 patients tested, 53 (42.4%) had abnormal autoantibodies (3.7% male, 96.3% female). The most frequent antibodies were anti-Ro52 (32.1%), anti-SSA (26.4%), and anti-β2-glycoprotein 1(26.4%). Follow-up of 137 patients, including 53 cases with abnormal autoantibodies, revealed no systemic symptoms related to CTDs. Conclusion: RM predominantly affects middle-aged women and is frequently associated with CTDs-related autoantibody abnormalities, though no patients developed systemic CTDs manifestations during follow-up.