Evaluation of hematological parameters and treatment response in patients with alopecia areata treated with diphenylcyclopropenone: an exploratory retrospective study

Aim Alopecia areata(AA) is a chronic, non-scarring inflammatory disorder that affects hair follicles on the scalp and body.It is increasingly recognized that AA is not merely a dermatological condition limited to localized hair loss but may also be associated with systemic inflammatory processes. Materials and methods This retrospective study included male and female patients older than 4 years of age who were treated with topical diphenylcyclopropenone(DPCP) for moderate-to-severe AA between August 2023 and August 2024.The study comprised 19 female and 19 male patients.Patients who received topical DPCP treatment for AA and underwent complete blood count(CBC) analysis both before and after treatment were included. Results Of the 38 AA cases included in the study, 19 were female(50.0%).The mean Severity of Alopecia Tool(SALT) score at baseline was 87.76 ± 21.80(range: 25-100), while the mean SALT score at Month 6 was 60.21±41.33(range: 0-100), indicating a significant reduction in disease severity(p < 0.01). Significant changes were observed in lymphocyte counts(p = 0.01) and the platelet-to-lymphocyte ratio(PLR, p = 0.02) following treatment.When evaluating which hematological and inflammatory parameters predicted the SALT score at Month 6, an exploratory regression analysis(Adjusted R² = 0.101) showed that only the change in lymphocyte levels was associated with treatment response(β = 0.354, p = 0.029). Conclusion Our findings suggest that, based on sixmonth evaluation results,DPCP may be an effective treatment option for AA.While it modulates local inflammation, it appears to have a limited effect on systemic immunity; however, this does not result in any significant adverse alterations in hematological and inflammatory biomarkers.Current data suggest that topical DPCP treatment demonstrated a potentially acceptable hematological safety profile in the short-tomedium term.Furthermore, the change in lymphocyte levels may emerge as a potential biomarker for predicting treatment response.