Onychomycosis: strategies to improve efficacy and reduce recurrence

Abstract

Fungal infections may be difficult to treat for several reasons. It is important to obtain the correct diagnosis, and select the appropriate antifungal agent and route. General considerations that may be associated with recurrent infections are, a genetic predisposition and suboptimal bioavailability of drug, resulting in insufficient concentration at the target site. The aetiologic organism, the severity of disease, other coexisting diseases, concomitant drug intake, and the presence of fungal infection at other sites are some factors that determine the choice of antifungal therapy and its route of administration, oral vs. topical lacquer. Local factors such as the thickness of the nail, presence of lateral onychomycosis, longitudinal spike, dermatophytoma and severe onycholysis are some factors that may determine the choice of secondary measures such as mechanical or topical treatment. Booster or supplemental therapy may be of benefit when the response to initial treatment is poorer than expected and unlikely to result in complete response. Steps should be taken to reduce the possibility of recurrence once cure has been achieved.

Pulse versus continuous terbinafine for onychomycosis: A randomized, double-blind, controlled trial

“…Although not formally studied in large, randomized, controlled trials, anecdotal evidence suggests that combination of avulsion (chemical or surgical) and oral therapy, often for more than 3 months, may achieve higher cure rates, 56 especially for nails with clinical patterns thought to be more resistant to therapy, including extensive onychauxis, lateral pattern, longitudinal spike, severe onycholysis, and dermatophytoma. 57 In the future, skin testing for dermatophyte reactivity may help guide therapy by indicating which patients need more than the standard 3 months of therapy. 58 This randomized, double-blind, controlled trial demonstrated the superiority of the standard continuous-dose terbinafine regimen over the considered pulse-dosing regimen for treatment of toenail onychomycosis, as measured by several different outcomes.…”

Fungal Infections From Human and Animal Contact

“…37 Prevention of recurrence of onychomycosis following clinical cure may be aided by periodic application of topical antifungal, specific to the nail and/or the plantar and interdigital foot; footwear decontamination; treatment of immediate family; and avoidance of public swimming pools. 59 To prevent transmission of dermatophyte spores from household pets, carpet cleaning, thorough laundering of clothes and bedding and changing of heating/cooling system filters are recommended. 52…”

Dermatophytosis (Tinea) and Other Superficial Fungal Infections

“…Within the spectrum of DLSO presentations, infections may spread relatively evenly across the nail plate. Alternatively, infection may penetrate only the lateral edge or edges of the nail (lateral infection), or may penetrate longitudinally in a "spike" formation [27]. Infection may also develop as a dermatophytoma, where debris and fungi clump densely to form a thick, hyperkeratotic mass [27].…”