Combination of Topical Anthralin and Calcipotriene in Alopecia Areata: A Discussion of the Mechanisms of Action

The document discusses a study that presented a combination of anthralin and calcipotriene as a treatment for alopecia areata (AA), suggesting it as an alternative for treatment-resistant cases. The study questions the rationale behind using topical vitamin D analogues like calcipotriene, which are believed to cause irritant dermatitis, a side effect occurring in only 10% to 15% of psoriatic subjects, and even less in healthy volunteers. The document also explores the immunomodulatory effects of vitamin D analogues, such as the enhancement of regulatory T cells and inhibition of CD8+ T-cell activation, which are more commonly postulated mechanisms in AA treatment. It is suggested that combining anthralin and calcipotriene might increase the activity of the anti-inflammatory cytokine IL-10, potentially mitigating the effects of proinflammatory cytokines in AA lesions. However, the exact mechanisms of anthralin or DPCP in AA management are not fully understood, and the potential synergy of combining these treatments remains to be studied. The document concludes that while the combination regimen may be valuable for treatment-resistant AA, further research is needed to understand the mechanisms of action.