A clinico- dermoscopic study of comparison of intralesional triamcinolone acetonide, pentoxifylline and their combination in treatment of alopecia areata

Alopecia areata (AA) is a common autoimmune disease that targets hair follicles with a prevalence of approximately 0.1% and a lifetime incidence of approximately 1.7%, which presents as patchy, non-scarring hair loss. 1

Pentoxifylline (PTX) is a methylxanthine derivative that acts as a phosphodiesterase inhibitor, raises the levels of cAMP in smooth muscle of the veins, and is known for its

vasodilator activity, and it is primarily used in microcirculatory disorders. PTX is sometimes regarded as a rheological agent because of its action on red blood cells. It enhances the resilience of erythrocytes and, besides, boosts blood supply in the arteries.

PTX has been used in dermatological disorders mostly as an adjunctive therapy with beneficial effects as it improves blood circulation and oxygen supply.3

The most common uses are peripheral vascular disease ,  vasculopathies and vasculitides, venous leg diseases and ulcers,  pigmented purpuric dermatoses, aphthosis and behcet’s disease, leprosy, AIDS , leishmaniasis, psoriasis, graft versus host disease, sarcoidosis, peyronie’s disease, radiation induced fibrosis and burns, keloids, scleroderma, morphea, oral submucous fibrosis, pseudoxanthoma elasticum, actinic prurigo, irritant and allergic hypersensitivity reactions, lipodermatosclerosis, ulcerating necrobiosis lipoidica, SJS and TEN. 4The synthesis of TNF-α, a large pro-inflammatory mediator with wide-spectrum activity and released mainly by mononuclear cells, is believed to be inhibited by PTX.

PTX pharmacological activity may have significant ramifications in medical disease processes where local and systemic regulation of TNF may be needed to regulate particular immune processes. 5

PTX, in addition to inhibiting the synthesis of TNF-α, appears to increase the divergence of the cell secretions more toward the manufacturing of TH 2 cytokines, suppressing, on the other hand, cytokines of the TH 1 subset, like IFN-γ.6

A systematic review and network meta-analysis, which included 54 RCTs consisting of 49 treatment options and 3149 patients, suggested that oral pentoxifylline plus topical corticosteroids had the highest treatment success rate compared to “no treatment,” although the superiority to many other treatments is uncertain. 7

Intralesional therapy has a number of advantages over topical therapy, including a faster and longer duration of action, penetration that is deeper than topical therapy, the removal of the need for long-term topical medication, and improved patient compliance. The effect of microneedling for the treatment of AA is supposed to stimulate the dermal papilla and stem cells by mechanical trauma and increase the blood supply to the hair follicles.

A previous study showed the intralesional injection of a combination of pentoxifylline and triamcinolone to be significantly superior to pentoxifylline alone, followed by triamcinolone alone, in the treatment of alopecia areata. 8

However, dermoscopic changes during treatment of alopecia and clinical resolution with pentoxifylline have not been studied. Hence, we aim to study the efficacy of pentoxifylline and the dermoscopic changes compared to triamcinolone in the treatment of alopecia areata.

References :

1.         Biran R, Zlotogorski A, Ramot Y. The genetics of alopecia areata: new approaches, new findings, new treatments. J Dermatol Sci. 2015 Apr;78(1):11–20.

2.         Ahmadi M, Khalili H. Potential benefits of pentoxifylline on wound healing. Expert Rev Clin Pharmacol. 2016;9(1):129–42.

3.         Çakmak SK, Çakmak A, Gönül M, Kiliç A, Gül Ãœ. Pentoxifylline use in dermatology. Inflamm Allergy Drug Targets. 2012 Dec;11(6):422–32.

4.                  Hassan I, Dorjay K, Anwar P. Pentoxifylline and its applications in dermatology. Indian Dermatol Online J. 2014 Oct;5(4):510-6.

5.         Strieter RM, Remick DG, Ward PA, Spengler RN, Lynch JP, Larrick J, et al. Cellular and molecular regulation of tumor necrosis factor-alpha production by pentoxifylline. Biochem Biophys Res Commun. 1988 Sep 30;155(3):1230–6.

6.         de Sá Oliveira T, Capp Neto M, Martins BJ, Rodrigues HA, Antonino RM, Magalhães AV. Action of pentoxifylline on experimental cutaneous leishmaniasis due to Leishmania (Leishmania) amazonensis. Mem Inst Oswaldo Cruz. 2000;95(4):477–82.

7.         Fukumoto T, Fukumoto R, Magno E, Oka M, Nishigori C, Horita N. Treatments for alopecia areata: A systematic review and network meta-analysis. Dermatologic Therapy. 2021;34(3):e14916.

8.         El‐Taweel A‐AI, Akl EM. Intralesional pentoxifylline injection in localized alopecia areata. J Cosmet Dermatol. 2019;18:602–60