Minoxidil for onychodystrophy: Can this hair loss remedy be a nail growth remedy?

Summary: Abstract Body: Onychodystrophy, often arising secondary to numerous etiologies, can be idiopathic. In these cases, a nail targeted therapy would be of great clinical utility. This systematic review evaluates the existing literature on minoxidil as a treatment for onychodystrophy. PubMed, Web of Science, and Scopus databases were searched following PRISMA 2020 guidelines using the following strategy: “Minoxidil AND nail.” Studies investigating minoxidil treatment of onychodystrophy were included. Background articles, systematic reviews, studies with nonhuman subjects, or articles in languages other than English were excluded. Among 137 articles identified, five were included, yielding 187 patients (51 male, 136 female). Four of five studies evaluated nail growth as an endpoint for minoxidil treatment (n=186), one evaluated nail appearance (n=66), one evaluated nail color (n=1), and one evaluated nail strength (n=66). Three of five studies used 5% topical minoxidil (n=120), one used 2% topical minoxidil (n=1), and one used 1.25 mg oral minoxidil daily (n=66). Topical minoxidil (5%) had significantly greater increases in nail growth at 28 days compared to oral biotin (2.5mg) (p<0.01). Oral minoxidil (1.25 mg) improved nail appearance in 36.4% of patients (n=24), nail growth in 53.0% of patients at month seven (n=35), and nail strength of 37.9% of patients at month eight (n=25). Daily topical minoxidil (2%) resolved nail discoloration within six months (n=1), with no remission at 72 months. All five studies (n=187) demonstrated statistically significant improvement in the measured onychodystrophy outcomes. These outcomes are hypothesized to be linked to increased endothelial growth factors in the area, resulting in improved perfusion to the nail matrix. This review collects all available data on the utility of minoxidil in treating onychodystrophy. While larger and more robust studies are needed to understand optimal dosing and administration regimens, these data are promising for improving nail color, texture, strength, and growth rate. Anagha Thiagarajan¹, Jack Woll¹, Milan M. Hirpara¹, Natasha Mesinkovska¹, Luke Horton¹ 1. University of California Irvine Department of Dermatology, Irvine, CA, United States. Clinical Research: Interventional Research