Tazarotene as alternative topical treatment for onychomycosis

Abstract

Elena Campione,1 Evelin Jasmine Paternò,2 Gaetana Costanza,2,3 Laura Diluvio,1 Isabella Carboni,1 Daniele Marino,4 Cartesio Favalli,4 Sergio Chimenti,1 Luca Bianchi,1 Augusto Orlandi2,3 1Department of Dermatology, 2Department of Biomedicine and Prevention, 3Department of Anatomic Pathology, Policlinic Tor Vergata, 4Department of Microbiology, University of Rome Tor Vergata, Rome, Italy Background: Distal and lateral onychomycoses are the most frequent forms of onychomycosis, causing subungual hyperkeratosis that usually limits local penetration of antimycotic drugs. Tazarotene exerts anti-inflammatory and immune-modulating activities toward both infective agents and damaged keratinocytes. Given the well-documented efficacy of tazarotene on hyperkeratotic nail psoriasis, we investigated its therapeutic use in onychomycosis. Patients and methods: We designed a preliminary open clinical trial in patients affected by distal and lateral subungual onychomycosis of the toenails and verified the fungistatic activity of tazarotene in vitro. Fifteen patients were treated with topical tazarotene 0.1% gel once per day for 12 weeks. Mycological cultures and potassium hydroxide stains of nail samples were performed at the beginning and at the end of the study. Treatment was considered effective when clinical healing and negative mycological culture were obtained. Onycholysis, nail bed discoloration, and subungual hyperkeratosis were measured using standardized methodologies and analyzed by means of Mann–Whitney test and analysis of variance. Fungistatic activity of tazarotene was evaluated by disk diffusion assay. Results: Six patients (40%) reached a mycological cure on target nail samples already after 4 weeks of treatment. Complete clinical healing and negative cultures were reached in all patients at week 12, with a significant improvement of all clinical parameters of the infected nails. Disk diffusion assay after 48 hours of incubation with tazarotene solution showed a central area of inhibition in all examined fungal cultures. Conclusion: Our results documented a good clinical outcome using topical tazarotene 0.1% gel in distal and lateral subungual onychomycosis and its fungistatic activity of tazarotene in vitro. The majority of patients appeared cured at a 6-month follow-up. The efficacy and safety of tazarotene must be confirmed on a larger number of patients, although already documented in nail psoriasis patients often affected by onychomycosis. Keywords: antiproliferative agent, retinoids, fungistatic activity