Topical Simvastatin Versus Topical Steroid in Treatment of Alopecia Areata

Overview

Alopecia areata (AA) is an autoimmune disorder characterized by non-scarring hair loss of the scalp or any hair-bearing surface. Alopecia areata affects approximately 2% of the general population. AA has a significant influence on patients' quality of life and may induce psychological disorders. In AA, CD4+ and CD8+ T-cells violate the immune privilege of the anagen hair follicle, leading to loss of the growing hair shaft. A genome-wide association study demonstrated a genetic predisposition to AA . Additionally, environmental insults, such as viral infections, trauma, or psychosocial stress, have also been suspected to possibly contribute to the development of the disease . The clinical manifestations of AA vary from small well-defined patches of hair loss to the diffuse involvement of the scalp or the entire body. The majority of AA patients experience unpredictable relapsing and remitting episodes. In a number of patients, it can be persistent, especially when the hair loss is extensive.

There are many treatment modalities for AA including topical treatment, intralesional injections, systemic corticosteroids, systemic immunosuppressants like methotrexate or cyclosporine, excimer laser and photochemotherapy . To date, the majority of traditional treatments for AA are of limited efficacy with a high risk of adverse effects . Topical corticosteroids are widely used in the treatment of limited patchy AA and as a first-line therapy for children. They are also recommended as an adjunctive therapy to systemic treatments in more severe forms . Statins are well known lipid-lowering medications. They have anti-inflammatory and immunomodulatory effects. Simvastatin belongs to the statin family. Lately, Simvastatin is utilized in treatment of several dermatological diseases . It showed efficacy in treatment of psoriasis, vitiligo, xanthomas , atopic dermatitis and acne vulgaris. In several case reports, AA patients were successfully treated with systemic simvastatin . DelCanto, 2020 studied the effect of topical simvastatin in animal model of AA and concluded that it induced hair re-growth, suggesting that it could be a new efficient therapy for AA. Statins are theorized to induce hair regrowth in AA by inhibiting signal transducers and activators of transcription (STAT) phosphorylation that activates several important inflammatory cytokines and also by altering the balance of Th1/Th2, suppressing IL-17, and inhibiting lymphocyte migration. Fractional laser has been reported to be successful in treating AA. Fractional CO2 laser is assumed to help in treatment of AA through stimulation of T-cell apoptosis, arrest of hair follicles in the telogen stage, and promotion of the anagen stage. Also, Fractional CO2 laser creates microchannels in the epidermis to improve drug delivery into the skin.