Efficacy of Intralesional and Oral Dutasteride in the Treatment of Androgenetic Alopecia: A Systematic Review

Androgenetic alopecia is the most common cause of hair loss [Br J Dermatol. 2011 Jan;164(1):5-15]. Finasteride and minoxidil are the only approved treatments [J Am Acad Dermatol. 2008 Oct;59(4):547-8 and J Eur Acad Dermatology Venereol. 2018 Jan;32(1):11-22]. Dutasteride is more potent than finasteride due to its ability to inhibit both 5-alpha-reductase type I and II [Our Dermatol Online. 2017 Sep;9(1):75-9] though its adverse effects and long half-life contribute to the reluctance on its oral use. Mesotherapy could be a feasible alternative to avoid systemic exposure and side effects [J Pan-Arab League Dermatologist. 2009 Feb;20(1):137-45]. We aim to perform a systematic review to analyze scientific literature with the purpose of comparing efficacy and adverse effects of both administration routes. Five clinical trials using oral route and 3 intralesional in comparison with placebo met criteria for inclusion. Regarding intralesional dutasteride, only one study [Clin Dermatol. 2001 Mar;19(2):149-54] reported the mean change in hair count. Although both interventions favor over placebo, there are not enough data to reliably compare outcomes obtained between both routes. Mean increase in hair count observed with oral dutasteride was higher (MD: 15.92 hairs [95% CI: 9.87-21.96]; p = I-2 = 90%) compared to intralesional dutasteride in Abdallah's study (MD: 7.90 hairs [95% CI: 7.14-8.66]; p = <0.00001). Future studies are required to assess the therapeutic efficacy of both treatment routes, including head-to-head treatments before well-supported conclusions can be established.