Methylene blue vs methyl aminolevulinate photodynamic therapy in the treatment of mild-to-moderate toenail onychomycosis: Short- and medium-term effects

Medium-term antifungal effects of methylene blue versus flavin mononucleotide in the treatment of moderate toenail onychomycosis

BACKGROUND

Methylene blue (MB) and flavin mononucleotide (FMN)-mediated photodynamic therapy (PDT) have demonstrated local antimicrobial effect, but no direct comparative study has been published so far for the treatment of toenail onychomycosis.

OBJECTIVES

To directly compare the short and medium-term efficacy of MB versus FMN as photosensitizers in PDT for toenail onychomycosis by applying them in a 40% w/w urea cream in two different dye concentrations.

METHODS

Forty toenails with distal and lateral subungual moderate onychomycosis due to dermatophyte fungi were randomised to receive 10 weekly sessions of PDT mediated by four topical formulations including MB or FMN at two different concentrations: Group I: 0.1% w/w MB; Group II: 2% w/w MB; Group III: 0.1% w/w FMN; and Group IV: 2% w/w FMN. Photographs were used for onychomycosis severity index (OSI) estimation allowing clinical assessment at any point of the study. Microscopic and microbiological evaluations were carried out at baseline, 27- and 35-week follow-ups. Side effects were recorded along with patient satisfaction.

RESULTS

At week 27, mycological cure rates were 60%, 30%, 50% and 40% and complete cure rates were 0%, 20%, 10% and 20%, for Groups I, II, III and IV respectively. At week 35, mycological cure rates were 70%, 70%, 70% and 60% and complete cure rates were 30%, 50%, 70% and 30%, for Groups I, II, III and IV respectively. All cream formulations were safe and patients were fairly satisfied.

CONCLUSIONS

Results of the present work confirm PDT as a therapeutic alternative for onychomycosis. Although all cream formulations were safe and effective, with a good degree of satisfaction, higher cure rates were obtained with 2% w/w MB cream and 0.1% w/w FMN cream.

A Review of the Dermatologic Clinical Applications of Topical Photodynamic Therapy

Topical photodynamic therapy is a widely approved therapy for actinic keratoses and low-risk nonmelanoma skin cancers with a rapidly growing range of emerging indications for other cutaneous diseases. This review summarizes the best-available evidence to provide a clinical update for dermatologists on the approved and emerging indications of photodynamic therapy. The body of evidence suggests that photodynamic therapy is superior or noninferior to other available treatment modalities for actinic keratoses, low-risk basal cell carcinomas, Bowen's disease, skin field cancerization, chemoprevention of keratinocyte carcinomas in organ transplant recipients, photoaging, acne vulgaris, and cutaneous infections including verrucae, onychomycosis, and cutaneous leishmaniasis. There is emerging evidence that photodynamic therapy plays a role in the management of actinic cheilitis, early-stage mycosis fungoides, extramammary Paget disease, lichen sclerosis, and folliculitis decalvans but there are no comparative studies with other active treatment modalities. Common barriers to topical photodynamic therapy include procedural pain, costs, and the time required for treatment delivery. There is significant heterogeneity in the photodynamic therapy protocols reported in the literature, including different photosensitizers, light sources, number of treatments, time between treatments, and use of procedural analgesia. Topical photodynamic therapy should be considered in the management of a spectrum of inflammatory, neoplastic, and infectious dermatoses. However, more comparative research is required to determine its role in the treatment algorithm for these dermatologic conditions and more methodological research is required to optimize photodynamic therapy protocols to improve the tolerability of the procedure for patients.

Urea versus fractional Er:YAG laser pretreatment of methylene blue photodynamic therapy in the treatment of moderate toenail onychomycosis: short- and medium-term effects

Keratolytic properties of urea 40% have long time used for the treatment of onychomycosis. Fractional ablative lasers enhance the delivery of topically applied photosensitizers improving photodynamic therapy (PDT) efficacy. The aim of this study was to compare the short- and medium-term efficacy of a pretreatment with urea 40% and fractional Er:YAG (Fr Er:YAG) laser radiation before PDT mediated by methylene blue (MB) for moderate toenail onychomycosis. Twenty-first-toe toenails were randomized to receive either urea 40% (Group I) or Fr Er:YAG laser (Group II) pretreatment and 9 sessions of MB/PDT over the course of 16 weeks. At baseline, 28- and 40-week follow-ups, clinical efficacy was assessed by digital photographs [allowing determination of the onychomycosis severity index (OSI)], whereas mycological efficacy was assessed by histological examination and fungal culture. Details of the side effects and patients' satisfaction were also recorded. In both groups, a significant decrease in OSI values was observed at the 28-week follow-up and a slight rebound at the 40-week follow-up. The percentage of nail involvement decreased significantly in both groups at the 28-week follow-up, to continue declining gently in Group I at 40 weeks, in contrast to the rebound observed during this period in Group II. The mycological cure rate was 20% and 30% at 28-week follow-up and 70% and 40% at 40-week follow-up, in Group I and II, respectively. Patients reported being fairly satisfied, and no side effects were detected in any groups. Although both pretreatments favor the action of PDT for the treatment of onychomycosis, the use of urea at 40% is more effective in the medium term.

Treatment of Superficial Mycoses Using Photodynamic Therapy: A Systematic Review and Meta-Analysis

Objective: The purpose of this study is to evaluate the effectiveness and safety of photodynamic therapy (PDT) in treating superficial fungal infections, and provide reference for clinical application. Methods: In accordance with Population, Intervention, Comparator, and Outcome (PICO), the research question and keywords were formulated. Records published in English by PubMed, Embase, Cochrane Library, and Web of Science as of November 14, 2022 were retrieved, including the keywords "mycoses," "tinea," "photochemotherapy," etc. Besides, meta-analysis performed by STATA and PROSPERO registration code was CRD42022363448. Results: One thousand four hundred eighty-four records were identified and 18 articles involving 343 patients with superficial fungal infections were enrolled. The overall mycological cure rate of PDT is 55% [95% confidence interval (CI): 0.46-0.65]. The fungal cure rate using methylene blue (MB) as photosensitizer (PS) is 67% (95% CI: 0.55-0.79); using 5-aminolevulinic acid is 34% (95% CI: 0.21-0.47); and using methyl aminolevulinate is 56% (95% CI: 0.33-0.78). The fungal cure rate of moderate-to-severe onychomycosis according to Onychomycosis Severity Index is 60% (95% CI: 0.47-0.73) and that of moderate onychomycosis is 66% (95% CI: 0.56-0.76). It was observed that the treatment parameters did not follow the same standard across studies. The majority of the included studies were moderate to low biased. Conclusions: PDT, particularly using MB as PS, has a certain mycological cure rate and safety at treating superficial mycoses. Due to the insufficient number of studies on PDT in the treatment of superficial fungal infections and the small sample size of some studies, more studies with standardized PDT parameters, large sample size, and long follow-up periods are needed to prove that PDT has the potential to become an alternative to traditional antifungal therapy or to find a better combination between them.

Fractional CO2 laser - assisted methylene blue photodynamic therapy is a potential alternative therapy for onychomycosis in the era of antifungal resistance

BACKGROUND

Treatment of onychomycosis is challenging by virtue of the impact of nail disfigurement, the location of the fungi within the nail and reported antifungal resistance worldwide. Light-based technologies are promising primary or adjunctive therapeutic modalities. We aimed to compare the efficacy of photodynamic therapy and fractional CO2 laser monotherapy either alone or in combination for onychomycosis.

PATIENTS AND METHODS

This prospective randomized comparative study was conducted on 51 onychomycosis patients divided into three groups. In group A, patients were treated using 6 photodynamic therapy sessions using methylene blue and IPL (560 to 700 nm, fluence 12 J/cm2). Group B patients were treated using 6 bimonthly fractional CO2 laser sessions (10,600 nm, 1.600 mj energy and 0.6 mm density) and group C patients were treated using 6 combined fractional CO2 laser and photodynamic therapy sessions. Patients were evaluated mycologically, dermoscopically and clinically by calculation of proximal nail diameter percentage at baseline, monthly, at the end of treatment and after a 6-month follow-up period post-treatment.

RESULTS

Candida was the most commonly isolated organismin in 64.7%, 70.6% and 70.6% of the pateints in groups A, B and C, respectively. The dermoscopic findings in the total dystrophic onychomycosis was subungual hyperkeratosis in 6 patients (100%), longitudinal streaks and striae in 1 patient (16.7%). In dorsolateral subungual onychomycosis, jagged proximal edge in 31 patients (70.5%), and pigmentation in 30 patients (68.2%) were noted. In proximal subungual onychomycosis irregular matt patches were seen in 1 patient (100%). Proximal nail diameter percentage showed statistically significant improvement after treatment and 6 months follow up in the 3 studied groups. Mean increase of proximal nail diameter after treatment was highest in group C (52.94 ± 20.24), followed by group B (43.82 ± 21.03) and least in group A (35.29 ± 17.0). This difference was statistically significant (p = 0.044). Reported side effects were mild-moderate pain, discoloration and paronychia.

CONCLUSION

We conclude that fractional CO2 laser and photodynamic monotherapy, and their combination achieve high success rates, good patient satisfaction and safety profile. Fractional CO2-assisted photodynamic therapy is associated with the highest improvement over either fractional CO2 or photodynamic therapy alone.

Combination of Photodynamic Therapy and Oral Antifungals for the Treatment of Onychomycosis

Onychomycosis accounts for 50% of nail disorders, making it one of the most prevalent fungal diseases and a therapeutic challenge. Photodynamic therapy (PDT) could constitute a therapeutic alternative, owing to its good adherence, the low probability of resistance, the lack of interaction with antimicrobials, and its favorable adverse effect profile. This retrospective observational study included all patients with a microbiological diagnosis of onychomycosis treated with PDT at Miguel Servet University Hospital, Zaragoza (Spain), between January 2013 and June 2021. The protocol consisted of pre-treatment with 40% urea for 7 days, followed by 16% methyl-aminolevulinate (MAL) for 3 h and subsequent irradiation with a red-light LED lamp (37 J/cm²), every 1 or 2 weeks. Combined treatment with oral and/or topical antifungals was recorded. Of the 20 patients included (mean age, 59 ± 17 years), 55% were men. The most frequently detected microorganism was Trichophyton rubrum (55%). The most commonly affected location was the feet (90%): 50% of these cases were associated with tinea pedis. The median (standard deviation) number of PDT sessions was 6 (2.8). PDT was combined with systemic terbinafine (250 mg/day) in 10 cases (in 8 cases, this was administered for only 1 month), and with topical terbinafine in 3 cases. A complete clinical response was achieved in 80% (16) of cases and microbiological cure in 60% (12). PDT is a therapeutic alternative for onychomycosis, and can be administered either in monotherapy or combined with antifungals, allowing for a reduction in the duration and possible adverse effects of antifungal treatment and achieving higher cure rates than those obtained with either treatment alone.

Combination Therapy Should Be Reserved as Second-Line Treatment of Onychomycosis: A Systematic Review of Onychomycosis Clinical Trials

Onychomycosis is the most common nail disease encountered in clinical practice. Its importance extends well beyond aesthetics, often causing pain, difficulty with ambulation and performing daily activities, and impairing quality of life. Many patients fail to achieve cure with antifungal monotherapy and recurrences are common. Combination therapy has therefore gained considerable interest, given the potential for drug synergy and prevention of antifungal resistance, but it has not been well studied. A systematic review of onychomycosis medication only, as well as medication and procedural (laser, debridement, photodynamic therapy), clinical or randomized controlled trials evaluating combination vs. monotherapies was performed. After exclusions, 30 studies were included in the final analysis. There were conflicting results for medication-only trials, with some showing significant benefit of combination therapy over monotherapy, however, trials were not robustly designed and lacked sufficient follow-up. Procedural studies also lacked long-term follow-up, and failed to demonstrate efficacy in some severe onychomycosis cases. Considering the high cure rates demonstrated in pivotal antifungal monotherapy trials, and conflicting results, costs, and safety concerns associated with combination therapy, we recommend that combination therapy be reserved as second-line treatment options in patients with poor prognostic factors or for those who failed monotherapy for onychomycosis.