Serotonin Expression in Lichen Planus Lesions and Its Relationship with Depression/Anxiety

BACKGROUND: Psychological factors such as stress, depression, and anxiety have been documented to contribute to the development of lesions in lichen planus (LP). OBJECTIVE: To evaluate the relationship between serotonin expression in LP lesions and depression/anxiety. METHODS: Forty patients (22 females, 18 males) with LP and 20 healthy control subjects were included in this study. The severity of LP was assessed with the palmar method (using the measurement of affected body surface area [BSA]). The depression and anxiety scores were measured with Beck's depression inventory (BDI) and Beck's anxiety inventory (BAI). The expression of serotonin was determined via immunohistochemistry in LP lesions and in the control group skin using a monoclonal antibody to serotonin. RESULTS: The skin biopsies of the LP patients had significantly higher levels of serotonin than those of the control subjects (p<0.001). In the LP patients, and there was a positive correlation between serotonin expression and LP severity (p=0.022). Based on the results from the BDI and BAI, there was a significant relationship between the severity of depression/anxiety and intensity of serotonin expression (p<0.001). CONCLUSION: Data from this study suggest that serotonin may have a possible role in the pathogenesis of LP. Further, the relationship between serotonin expression in acute cutaneous lesions and the depression/anxiety scores indicates that serotonin may be a mediator for the association of LP and depression/anxiety simultaneously. There is a need for more specific studies showing the expression of serotonin in the lichen planus to demonstrate the cause or effect.