An update on photodynamic therapies in the treatment of onychomycosis

Abstract

Onychomycosis is a common fungal infection of the nails that is increasing in prevalence in the old, diabetics and immunocompromised. Onychomycosis presents a therapeutic challenge that can lead to significant reductions in quality of life leading to both physical and psychological consequences. Current treatment modalities are difficult to implement due to the poor penetration of topical treatments to the nail bed, the slow growing nature of nails and the need for prolonged use of topical and/or oral medications. Standard of care medications have cure rates of 63-76% that leads to a high propensity of treatment failures and recurrences. Photodynamic therapy (PDT) offers an alternative treatment for onychomycosis. Methylene blue dye, methyl-aminolevulinate (MAL) and aminolevulinic acid (ALA) have been used as photosensitizers with approximately 630 nm light. These modalities are combined with pre-treatment of urea and/or microabrasion for better penetration. PDT treatments are well tolerated with only mild transient pain, burning and erythema. In addition, significant cure rates for patients who have contraindications to oral medications or failed standard medications can be obtained. With further enhancements in photosensitizer permeability, decreased pre-treatment and photosensitizer incubation times, PDT can be a more efficient and cost-effective in office based treatment for onychomycosis. However, more large-scale randomized control clinical trials are needed to access the efficacy of PDT treatments.

Photodynamic Therapy and Skin Appendage Disorders: A Review

“…Onychomycosis presents a therapeutic challenge that can lead to significant reductions in quality of life leading to both physical and psychological consequences. Current treatment modalities are difficult to implement due to the poor penetration of topical treatments to the nail bed, the slow growing nature of nails and the need for prolonged use of topical and/or oral medications [77] . Nail psoriasis is estimated to affect 80% of psoriatic patients at some time during their lives [78] .…”

Efficiency of methylene blue‐mediated photodynamic therapy vs intense pulsed light in the treatment of onychomycosis in the toenails

“…Most of the published studies on PDT in onychomycosis treatment are based on the use of ALA (5‐aminolevulinic acid) or MAL (methyl aminolevulinate) as photosensitizer, eg, the works of Harris and Pierpoint 2012; Kamp et al 2005; Gilaberte et al 2017 . However, PDT mediated by MB has been proven in a head‐to‐head trial to be better than the standard of care . Methylene Blue is well known to be photodynamically active, in contrast to ALA or MAL which act as pro‐drugs when taken up by the target inducing the accumulation of endogenous PS and, consequently MB allows a quite immediate PDT (very short incubation time of 3 minutes compared to 3‐5 hours of ALA or 3 hours for MAL) without the needed of using occlusive dressing.…”

“…Most of the 30% of patients in the PDT group and the 20% in IPL group, who did not obtain complete cure [33][34][35] However, PDT mediated by MB has been proven in a head-to-head trial to be better than the standard of care. 36 has been in use for many years. 37 The characteristic colour of MB is caused by the strong absorption band in the 550-700 nm region with maximum molar absorptivity of 85 000 M -1 cm -1 at 664 nm.…”

Photodynamic therapy in the treatment of onychomycosis – a review

“…There are a number of methods of treating onychomycosis including topical lacquers, ointments, oral antifungal drugs, and surgical and chemical nail plate removal. Recently, attention has also been focused on the possibilities of applying PDT in the treatment of mycosis [23,24].…”

“…miejscowe lakiery, maści, doustne leki przeciwgrzybicze, chirurgiczne i chemiczne usuwanie płytki paznokciowej. Ostatnio zwraca się uwagę na możliwość wykorzystania PDT w leczeniu grzybicy [23,24].…”