Onychomycosis: Old and New

Abstract

Onychomycosis is a common chronic fungal infection of the nail that causes discoloration and/or thickening of the nail plate. Oral agents are generally preferred, except in the case of mild toenail infection limited to the distal nail plate. Terbinafine and itraconazole are the only approved oral therapies, and fluconazole is commonly utilized off-label. Cure rates with these therapies are limited, and resistance to terbinafine is starting to develop worldwide. In this review, we aim to review current oral treatment options for onychomycosis, as well as novel oral drugs that may have promising results in the treatment of onychomycosis.

Efficacy of topical trichloroacetic acid 100% either alone or combined with topical tioconazole 28% versus systemic itraconazole in the treatment of onychomycosis

“…The topical antifungals are rarely effective due to their limited penetration of the nail plate. 3,10 Recent researches have reported the antifungal effects of keratolytics including TCA 100%, suggesting its role as adjuvant treatment for onychomycosis. 6,7 The suggested mechanisms of TCA in treatment of onychomycosis are related to its ability to acidify the nail and subsequently blocks fungal spreading, thereby allowing the rapid regrowth of normal nail plate.…”

“…The treatment of onychomycosis is commonly associated with high recurrence rates and treatment failure. The topical antifungals are rarely effective due to their limited penetration of the nail plate 3,10 …”

“…1,2 The treatment of onychomycosis is still challenging due to the limited penetration of topical antifungals and the long duration needed for treatment which subsequently increases the risk of drug interactions, side effects and fungal resistance. 3…”

Novel Henna-Related Naphthazarine Photosensitizers for an Effective Photodynamic Therapy of Onychomycosis

“…However, the clinical efficacy of these topical antimycotics used to date for the treatment of onychomycosis has proven to be inadequate in numerous studies on patients. − The main reasons here are, above all, the poor bioavailability of the active ingredients in the nail compartment and hence the extremely long application periods required by the patients with correspondingly high demands on adherence . If topical treatment of onychomycosis was not successful and/or mycosis has already spread to larger areas of the nails, combination therapy with oral antifungals may be necessary to prevent the risk of systemic mycosis, e.g., an internal organ infestation by fungi . As with the topical treatment variant, oral or parenteral antimycotic therapy also requires a long application time since the systemically administered active ingredients have to accumulate in the keratin of the nail .…”

“…Photodynamic therapy (PDT) represents a realistic alternative for the treatment of onychomycosis. , However, previous studies have used photosensitizers such as methylene blue, which were not optimized for their intended use in the nail regarding keratinophilic features. Thus, from a pharmaceutical/medical point of view, there is an unmet need for innovation toward novel therapeutic options to treat onychomycosis in nails …”