Treatment Failures and Relapses in Onychomycosis: A Stubborn Clinical Problem

Abstract

The therapeutic outcome of onychomycoses is uncertain. Comparative short-term efficacy studies on antifungals abound and report contradictory findings. Few unbiased follow-up studies have scrutinized the long-term outcome. Basically, none of the current antifungals can guarantee cure in all instances. In addition, relapses are not rare. The causes of therapeutic failure in onychomycoses are multiple. The most important are the lack of diagnostic accuracy, inadequate antifungal choice or delivery modality, and presence of dormant conidia, sequestrated mycelium pockets or resistant fungal species. The concept of fungicidal drug derived from selected in vitro studies appears irrelevant in clinical practice.

Microemulsion-Based Gel of Terbinafine for the Treatment of Onychomycosis: Optimization of Formulation Using D-Optimal Design

“…Yeasts (Candida albicans, Candida parapsilosis) are also responsible in some cases. Toe nails are frequently affected than finger nails, due to their slower growth and more susceptibility to infections (2,3).…”

UV-curable gels as topical nail medicines:In vivo residence, anti-fungal efficacy and influence of gel components on their properties

“…The disease is often of long duration, is 'more than a cosmetic problem' (Scher,42 1994), significantly affects patients' quality of life (Lubeck et al, 1993) and is recalcitrant to 43 treatment (Arrese and Pierard, 2003;Daniel and Jellinek, 2010). Oral therapy with anti- 44 fungal agents, such as terbinafine and itraconazole, is the treatment mainstay.…”

Spores, Sporodochia and Fomites in Onychomycosis

“…Histomycology refers to the histological examination of nail clippings searching for onychomycosis [3,4,5,6,7,8,9,10]. Three groups of fungi can cause onychomycosis, namely the dermatophytes, yeasts and nondermatophyte moulds.…”

“…Various combinations of these fungi may also be involved. Although the role for the nondermatophyte fungi as true primary pathogens remains a matter of debate, they represent a substantial proportion of isolates from nails [3,4,5,6,7,8,9,10]. The aspect of the microorganisms is variable according to their nature, basically presenting as hyphae, yeasts and spores (fig.…”

“…On the other hand, arthroconidia and chlamydoconidia (fig. 4) are found admixed with invasive mycelia [3,5,6,7, 10]. A sporodochium has not been described so far in onychomycosis.…”