Distal and lateral toenail onychomycosis caused by Trichophyton rubrum: treatment with photodynamic therapy based on methylene blue dye

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.

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.

Updated Perspectives on the Diagnosis and Management of Onychomycosis

Onychomycosis is the most common nail disease encountered in clinical practice and can cause pain, difficulty with ambulation, and psycho-social problems. A thorough history and physical examination, including dermoscopy, should be performed for each patient presenting with nail findings suggestive of onychomycosis. Several approaches are available for definitive diagnostic testing, including potassium hydroxide and microscopy, fungal culture, histopathology, polymerase chain reaction, or a combination of techniques. Confirmatory testing should be performed for each patient prior to initiating any antifungal therapies. There are several different therapeutic options available, including oral and topical medications as well as device-based treatments. Oral antifungals are generally recommended for moderate to severe onychomycosis and have higher cure rates, while topical antifungals are recommended for mild to moderate disease and have more favorable safety profiles. Oral terbinafine, itraconazole, and griseofulvin and topical ciclopirox 8% nail lacquer, efinaconazole 10% solution, and tavaborole 5% solution are approved by the Food and Drug Administration for treatment of onychomycosis in the United States and amorolfine 5% nail lacquer is approved in Europe. Laser treatment is approved in the United States for temporary increases in clear nail, but clinical results are suboptimal. Oral fluconazole is not approved in the United States for onychomycosis treatment, but is frequently used off-label with good efficacy. Several novel oral, topical, and over-the-counter therapies are currently under investigation. Physicians should consider the disease severity, infecting pathogen, medication safety, efficacy and cost, and patient age, comorbidities, medication history, and likelihood of compliance when determining management plans. Onychomycosis is a chronic disease with high recurrence rates and patients should be counseled on an appropriate plan to minimize recurrence risk following effective antifungal therapy.

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.

The evolution of clinical guidelines for antimicrobial photodynamic therapy of skin

Antimicrobial photodynamic therapy has become an important component in the treatment of human infection. This review considers historical guidelines, and the scientific literature to envisage what future clinical guidelines for treating skin infection might include. Antibiotic resistance, vertical and horizontal infection control strategies and a range of technologies effective in eradicating microbes without building up new resistance are described. The mechanism of action of these treatments and examples of their clinical use are also included. The research recommendations of NICE Guidelines on the dermatological manifestations of microbial infection were also reviewed to identify potential applications for PDT. The resistance of some microbes to antibiotics can be halted, or even reversed through the use of supplementary drugs, and so they are likely to persist as a treatment of infection. Conventional PDT will undoubtedly continue to be used for a range of skin conditions given existing healthcare infrastructure and a large evidence base. Daylight PDT may find broader antimicrobial applications than just Acne and Cutaneous Leishmaniasis, and Ambulatory PDT devices could become popular in regions where resources are limited or daylight exposure is not possible or inappropriate. Nanotheranostics were found to be highly relevant, and often include PDT, however, new treatments and novel applications and combinations of existing treatments will be subject to Clinical Trials.

Photodynamic disinfection and its role in controlling infectious diseases

Photodynamic therapy is witnessing a revival of its origins as a response to the rise of multi-drug resistant infections and the shortage of new classes of antibiotics. Photodynamic disinfection (PDDI) of microorganisms is making progresses in preclinical models and in clinical cases, and the perception of its role in the clinical armamentarium for the management of infectious diseases is changing. We review the positioning of PDDI from the perspective of its ability to respond to clinical needs. Emphasis is placed on the pipeline of photosensitizers that proved effective to inactivate biofilms, showed efficacy in animal models of infectious diseases or reached clinical trials. Novel opportunities resulting from the COVID-19 pandemic are briefly discussed. The molecular features of promising photosensitizers are emphasized and contrasted with those of photosensitizers used in the treatment of solid tumors. The development of photosensitizers has been accompanied by the fabrication of a variety of affordable and customizable light sources. We critically discuss the combination between photosensitizer and light source properties that may leverage PDDI and expand its applications to wider markets. The success of PDDI in the management of infectious diseases will ultimately depend on the efficacy of photosensitizers, affordability of the light sources, simplicity of the procedures, and availability of fast and efficient treatments.

In vitro evaluation of photodynamic activity of methylene blue against Trichophyton verrucosum azole-susceptible and -resistant strains

The intense search for the "Holy Grail" of antifungal therapy can be observed today. The searches are not limited only to discovery of potential antifungal drugs, but also new therapeutic strategies involving the use of chemosensitizers to achieve synergistic effect or physicochemical factors inducing stress conditions in fungal cells. In this study was examined in vitro effectiveness of photodynamic antifungal strategy with methylene blue using a light beam with a wavelength equal to 635 nm toward the Trichophyton verrucosum susceptible and itraconazole- and/or fluconazole-resistant strains. Methylene blue used at concentration equal to 5 μg/mL and in the presence of 40 J/cm² of light energy showed fungicidal effect toward the susceptible strains. However, for azole-resistant isolates, only the energy dose equal to 60 J/cm² at 5 μg/mL of methylene blue allowed to kill the pathogen. This study confirms that methylene blue induced by red light has a definite inhibitory effect on zoophilic dermatophytes.

Methylene blue-mediated photodynamic therapy may be superior to 5% amorolfine nail lacquer for non-dermatophyte onychomycosis

BACKGROUND

Methylene blue-mediated photodynamic therapy as an antimicrobial has been reported to improve onychomycosis.

OBJECTIVES

To compare the short-term efficacy of methylene blue-mediated photodynamic therapy (MB-PDT) and 5% amorolfine nail lacquer (AMO) for toenail onychomycosis using higher intensity and shorter total treatment period than previously reported.

METHODS

Twenty-seven toenails with onychomycosis were randomized to receive either six biweekly sessions of MB-PDT or AMO for twelve weeks. Dermoscopic photography was used for onychomycosis severity index assessment under a dermoscopic inspection (d-OSI) at baseline, weeks 6, 10, 14 and 22 as well as microscopic and microbiological tests. Adverse events were recorded.

RESULTS

All subjects completed the study. Causative organisms found were exclusively non-dermatophytes including Fusarium spp., Asperillus spp.,and yeasts. Fifteen toenails received MB-PDT, whilst 12 received AMO. D-OSI showed greater improvement in MB-PDT than in AMO groups at weeks 6, 10, 14 as well as 22, with median changes of -2, -3, -4 (P = .055). and - 3 respectively in the MB-PDT group. The AMO group displayed the median d-OSI change of 0 throughout the study period. Mycological cure rate at 22 weeks in MB-PDT and AMO group was 73.3% and 66.67% (P > .05). Clinical cure rate at 22 weeks in MB-PDT (26.7%) was higher than AMO (16.7%), (P > .05). All patients only felt comfortably warm during the MB-PDT treatment. No major adverse events were found in both groups.

CONCLUSIONS

MB-PDT appeared to be more efficacious for non-dermatophyte onychomycosis than AMO particularly in a limited period and moderately severe onychomycosis.

Investigation of the Dual-Stage Method of Active Er:YLF Laser Drug Delivery Through the Nail and Laser-Induced Transformations of the Drug Extinction Spectrum

BACKGROUND AND OBJECTIVE

A novel dual-stage method for active laser drug delivery (DSLADD) in the treatment of nail diseases is being presented. This method includes sequentially performed microporation of the nail with submillisecond pulses of Er:YLF laser radiation through a layer of an aqueous solution of drug deposited on the nail surface (Stage 1) and exposure this layer to the same laser radiation to deliver drug under the nail plate (Stage 2). The delivery of methylene blue (MB) as one of the possible drugs in the treatment of nail diseases is investigated. The influence of the thickness of the MB layer, as well as the energy and number of applied laser pulses, on the rate of active laser delivery is discussed. To illustrate the possible effect of delivery on the drug delivered, special attention is paid to the deformation of the extinction spectrum of MB solution after laser irradiation.

STUDY DESIGN/MATERIALS AND METHODS

Diode-pumped Er:YLF laser was used for DSLADD. The process of DSLADD under the nail plate was investigated using digital video microscopy. For different values of the thickness of MB solution layer applied to the nail plate and the energy of laser pulses, the number of laser pulses required to create a single through a microchannel in the nail plate and the number of laser pulses required to deliver the solution to the ventral side of the nail plate after its microporation were registered. The mass and the dose of MB solution penetrated under the nail plate, and the rate of MB solution delivery through a single microchannel was determined. Investigation of the influence of Er:YLF laser radiation parameters on the extinction spectrum of the drug was performed using a fiber spectrometer. The extinction spectra of the 0.001% aqueous solution of MB were recorded before and after exposure to a different number of Er:YLF laser pulses with the energy of 1-4 mJ.

RESULTS

It was found that the minimum number of laser pulses required for active Er:YLF laser drug delivery under the nail corresponds to the MB layer thickness of 100 μm and the laser pulse energy of 4 mJ. It is shown that in this case, the rate of active laser delivery of MB solution reaches 0.26 ± 0.03 mg/pulse. The radiation of the Er:YLF laser affects the shape of the extinction spectrum of the aqueous solution of MВ, which is associated with the transition of the dye from the monomeric to dimeric state. Depending on the laser pulse energy, the fraction of a certain conformational state in the aqueous MB solution can decrease or increase, stimulating a possible change in its photodynamic and antiseptic activity.

CONCLUSION

For the first time, a novel DSLADD through the nail has been described and investigated in vitro. It was demonstrated that at Er:YLF laser pulse repetition rate of f = 30 Hz, microporation of the nail plate and drug delivery through a single microchannel will be about 1.5 s. Lasers Surg. Med. © 2021 Wiley Periodicals LLC.

Different susceptibility of spores and hyphae of Trichophyton rubrum to methylene blue mediated photodynamic treatment in vitro

BACKGROUND

In recent years, methylene blue mediated-photodynamic therapy (MB-PDT) has proved to be an effective inhibitor to a variety of microorganisms, including Trichophyton rubrum, the most common dermatophyte worldwide. However, previous studies mainly focused on the spore form of T rubrum, but rarely on its hyphal form, although the latter is the main pathogenic form of T rubrum in vivo.

OBJECTIVE

To investigate the inhibitory effect of MB-PDT on T rubrum in different growth phases in vitro.

METHODS

The suspensions of spores and hyphae obtained from T rubrum (ATCC28188) were prepared, respectively, incubated with MB solution (0.15-40 μg/mL) and irradiated with 635 nm red light. Varied light energy and MB concentration were used. The specimen in the absence of light exposure or/and MB served as controls. MIC determination, colony counts and MTT assay were employed to evaluate the antifungal effect of MB-PDT.

RESULTS

The MICs of MB-PDT for hyphae and spores of T. rubrum were 6.300 ± 1.072 μg/mL and 1.984 ± 1.072 μg/mL, respectively, at a fixed light dose of 60 J/cm² . CFU counts gave the minimum critical combinations of MB concentration and light dose to achieve 100% inhibitory rate. For hyphae, they were 5 μg/mL + 100 J/cm² or 10 μg/mL + 60 J/cm² . For spores, they were 1.25 μg/mL + 40 J/cm² or 5 μg/mL + 20 J/cm² . The outcomes of MTT assay were consistent with those of CFU counts, but less accurate.

CONCLUSION

MB-PDT is a potent inhibitor to both spores and hyphae of T. rubrum in vitro, and the spores are more sensitive to it. Its antifungal efficacy is positively correlated with the concentration of MB and light dose.

Methylene blue vs methyl aminolevulinate photodynamic therapy in combination with oral terbinafine in the treatment of severe dermatophytic toenail onychomycosis: Short- and long-term effects

BACKGROUND

Photodynamic therapy (PDT) kills target microorganisms via reactive oxygen species (ROS) production. PDT seems to be a good alternative treatment option for onychomycosis.

OBJECTIVE

To compare the efficacy of combined therapies based on oral terbinafine (TN) plus adjunctive PDT mediated by methylene blue (MB) (TN + MB/PDT) or methyl aminolevulinate (MAL) (TN + MAL/PDT) in the treatment of onychomycosis.

METHODS

Twenty patients affected by severe dermatophyte onychomycosis in the nails of the big toe (>60% disease involvement of target nail) received oral TN for 12 weeks and concomitantly were randomly allocated to receive nine sessions, separated by 2-week intervals, of urea (40%) plus a PDT protocol mediated by MB (TN + MB/PDT: group I) or mediated by MAL (TN + MAL/PDT: group II). Clinical and mycological efficacy was evaluated at 16-, 40- and 52-week follow-up.

RESULTS

Both protocols showed a significant decrease in Onychomycosis Severity Index (OSI) scores (P < .05), from 24.2 ± 4.6 to 0.7 ± 0.6 (group I)) and from 18.5 ± 10.1 to 2.1 ± 2.0 (group II). No side effects or complications were reported in any of the combinations used. Mycological cure rates were significantly higher during the last third of the evaluated period of time, reaching 100% and 90% in group I and group II, respectively, at the 52-week follow-up. In both modalities, complete cure was achieved in 70% of the patients at the 52-week follow-up.

CONCLUSIONS

TN + MB/PDT and TN + MAL/PDT show similar outcomes in the treatment of toenails with severe onychomycosis. PDT is an effective method to accelerate the TN-mediated healing process.

Fractional CO2-assisted photodynamic therapy improves the clinical outcome and patient's satisfaction in toenail onychomycosis treatment: an intra-patient comparative single-center study

Background: Device-based therapies have been used for onychomycosis patients with intolerance to systemic treatments. Photodynamic therapy (PDT) improves onychomycosis, while fractional carbon dioxide (FrCO₂) augments the topical drug delivery. Comparative studies between PDT alone and laser-assisted one are lacking.Objective: We aimed to evaluate the efficacy of PDT alone versus FrCO₂-assisted PDT for treatment of onychomycosis.Methods: Twenty-one patients with bilateral onychomycosis of toenails with nearly the same degree of affection were enrolled in this prospective intra-patient-controlled study. The right affected toenail was treated via PDT alone. The left toenail was treated via a FrCO₂ followed immediately by PDT. The sessions were bimonthly for a total of six sessions. Direct microscopy, fungal cultures, clinical evaluation, onychomycosis severity index scoring, and patient's satisfaction were assessed before and 12 weeks after the last session.Results: Both treatments reduced significantly the onychomycosis severity index (p < .05) without significant difference between them. The improvement in nail appearance and patient's satisfaction were higher in laser-assisted PDT than PDT alone (p < .05).Conclusion: Both treatments effectively reduced the severity of onychomycosis with a high degree of safety and tolerability. Fractional CO₂-assisted PDT enhanced the clinical outcome via improving the nail appearance and patient's satisfaction.Key messagePhotodynamic therapy has a good success rate in clearing onychomycosis. Addition of fractional CO₂ to photodynamic therapy improves the nail appearance and induces better satisfaction to treatment.

A Critical Reappraisal of Off-Label Use of Photodynamic Therapy for the Treatment of Non-Neoplastic Skin Conditions

BACKGROUND

In the past 30 years, topical photodynamic therapy (PDT) has been investigated for the treatment of a broad spectrum of cosmetic, inflammatory, and infectious skin conditions with variable, and often contrasting, results. However, the non-expert clinician may be in difficulty evaluating these results because different sensitizers, concentrations, formulations, light sources, and irradiation protocols have been used. In addition, many of these studies have poor quality design being case reports and uncontrolled studies of few cases.

SUMMARY

With the aim to clarify the potential usefulness of PDT for the treatment of infectious and inflammatory skin diseases as well as selected cosmetic indications, we searched for randomized controlled clinical trials, non-randomized comparative studies, retrospective studies, and case series studies with a number of at least 10 patients, published since 1990. Later, we reappraised the results in order to give a simple critical overview. Key Messages: Evidence from the literature seems to strongly support the use of ALA- and MAL-PDT for the treatment of common skin diseases such as acne, warts, condylomata, and Leishmania skin infection and for photorejuvenation, i.e., the correction of selected cosmetic changes of aging and photoaging. For other disorders, the level of evidence and strength of recommendation are lower, and controlled randomized studies with prolonged follow-ups are necessary in order to assess the clinical usefulness and other potential advantages over current treatment options.

In vitro antifungal susceptibility testing of fungi in patients with onychomycosis

Onychomycosis is the most common nail disorder. To examine in vitro antifungal susceptibility of fungi among onychomycosis patients. The study included 68 patients with onychomycosis. Nail specimens were cultured on Sabouraud dextrose agar and Dermasel agar base-media. Isolated fungi were subjected to antifungal susceptibility tests against terbinafine, itraconazole, fluconazole, and griseofulvin. Candida species (Candida spp.) were detected in 32.4% of the cases of candidal onychomycosis (n = 37), 23.5% of the cases of distal and lateral subungual onychomycosis (n = 17), and 21.4% of the cases of total dystrophic onychomycosis (n = 14). Candida spp. were sensitive to fluconazole in 73.5%, itraconazole in 58.8%, and terbinafine in 5.9% of the cases. Aspergillus spp. were sensitive to itraconazole in all cases, and terbinafine in 87.5% of cases. Penicillium spp. were sensitive to itraconazole and terbinafine in 88.9% and 77.8% of cases, respectively. Trichophyton spp. were sensitive to terbinafine and resistant to itraconazole. Microsporum spp. were sensitive to itraconazole and resistance to terbinafine. All isolated fungi were resistant to griseofulvin. An increasing proportion of Candida spp. was observed among patients with different clinical varieties of onychomycosis. Candida spp. were highly sensitive to fluconazole and a lesser extent to itraconazole.

Topical and device-based treatments for fungal infections of the toenails

BACKGROUND

Onychomycosis refers to fungal infections of the nail apparatus that may cause pain, discomfort, and disfigurement. This is an update of a Cochrane Review published in 2007; a substantial amount of new research warrants a review exclusively on toenails.

OBJECTIVES

To assess the clinical and mycological effects of topical drugs and device-based therapies for toenail onychomycosis.

SEARCH METHODS

We searched the following databases up to May 2019: the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase and LILACS. We also searched five trials registers, and checked the reference lists of included and excluded studies for further references to relevant randomised controlled trials.

SELECTION CRITERIA

Randomised controlled trials of topical and device-based therapies for onychomycosis in participants with toenail onychomycosis, confirmed by positive cultures, direct microscopy, or histological nail examination. Eligible comparators were placebo, vehicle, no treatment, or an active topical or device-based treatment.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Primary outcomes were complete cure rate (normal-looking nail plus fungus elimination, determined with laboratory methods) and number of participants reporting treatment-related adverse events.

MAIN RESULTS

We included 56 studies (12,501 participants, average age: 27 to 68 years), with mainly mild-to-moderate onychomycosis without matrix involvement (where reported). Participants had more than one toenail affected. Most studies lasted 48 to 52 weeks; 23% reported disease duration (variable). Thirty-five studies specifically examined dermatophyte-caused onychomycosis. Forty-three studies were carried out in outpatient settings. Most studies assessed topical treatments, 9% devices, and 11% both. We rated three studies at low risk of bias across all domains. The most common high-risk domain was performance bias. We present results for key comparisons, where treatment duration was 36 or 48 weeks, and clinical outcomes were measured at 40 to 52 weeks. Based on two studies (460 participants), compared with vehicle, ciclopirox 8% lacquer may be more effective in achieving complete cure (risk ratio (RR) 9.29, 95% confidence interval (CI) 1.72 to 50.14; low-quality evidence) and is probably more effective in achieving mycological cure (RR 3.15, 95% CI 1.93 to 5.12; moderate-quality evidence). Ciclopirox lacquer may lead to increased adverse events, commonly application reactions, rashes, and nail alteration (e.g. colour, shape). However, the 95% CI indicates that ciclopirox lacquer may actually make little or no difference (RR 1.61, 95% CI 0.89 to 2.92; low-quality evidence). Efinaconazole 10% solution is more effective than vehicle in achieving complete cure (RR 3.54, 95% CI 2.24 to 5.60; 3 studies, 1716 participants) and clinical cure (RR 3.07, 95% CI 2.08 to 4.53; 2 studies, 1655 participants) (both high-quality evidence) and is probably more effective in achieving mycological cure (RR 2.31, 95% CI 1.08 to 4.94; 3 studies, 1716 participants; moderate-quality evidence). Risk of adverse events (such as dermatitis and vesicles) was slightly higher with efinaconazole (RR 1.10, 95% CI 1.01 to 1.20; 3 studies, 1701 participants; high-quality evidence). No other key comparison measured clinical cure. Based on two studies, compared with vehicle, tavaborole 5% solution is probably more effective in achieving complete cure (RR 7.40, 95% CI 2.71 to 20.24; 1198 participants), but probably has a higher risk of adverse events (application site reactions were most commonly reported) (RR 3.82, 95% CI 1.65 to 8.85; 1186 participants (both moderate-quality evidence)). Tavaborole improves mycological cure (RR 3.40, 95% CI 2.34 to 4.93; 1198 participants; high-quality evidence). Moderate-quality evidence from two studies (490 participants) indicates that P-3051 (ciclopirox 8% hydrolacquer) is probably more effective than the comparators ciclopirox 8% lacquer or amorolfine 5% in achieving complete cure (RR 2.43, 95% CI 1.32 to 4.48), but there is probably little or no difference between the treatments in achieving mycological cure (RR 1.08, 95% CI 0.85 to 1.37). We found no difference in the risk of adverse events (RR 0.60, 95% CI 0.19 to 1.92; 2 studies, 487 participants; low-quality evidence). The most common events were erythema, rash, and burning. Three studies (112 participants) compared 1064-nm Nd:YAG laser to no treatment or sham treatment. We are uncertain if there is a difference in adverse events (very low-quality evidence) (two studies; 85 participants). There may be little or no difference in mycological cure at 52 weeks (RR 1.04, 95% CI 0.59 to 1.85; 2 studies, 85 participants; low-quality evidence). Complete cure was not measured. One study (293 participants) compared luliconazole 5% solution to vehicle. We are uncertain whether luliconazole leads to higher rates of complete cure (very low-quality evidence). Low-quality evidence indicates there may be little or no difference in adverse events (RR 1.02, 95% CI 0.90 to 1.16) and there may be increased mycological cure with luliconazole; however, the 95% CI indicates that luliconazole may make little or no difference to mycological cure (RR 1.39, 95% CI 0.98 to 1.97). Commonly-reported adverse events were dry skin, paronychia, eczema, and hyperkeratosis, which improved or resolved post-treatment.

AUTHORS' CONCLUSIONS

Assessing complete cure, high-quality evidence supports the effectiveness of efinaconazole, moderate-quality evidence supports P-3051 (ciclopirox 8% hydrolacquer) and tavaborole, and low-quality evidence supports ciclopirox 8% lacquer. We are uncertain whether luliconazole 5% solution leads to complete cure (very low-quality evidence); this outcome was not measured by the 1064-nm Nd:YAG laser comparison. Although evidence supports topical treatments, complete cure rates with topical treatments are relatively low. We are uncertain if 1064-nm Nd:YAG laser increases adverse events compared with no treatment or sham treatment (very low-quality evidence). Low-quality evidence indicates that there is no difference in adverse events between P-3051 (ciclopirox hydrolacquer), luliconazole 5% solution, and their comparators. Ciclopirox 8% lacquer may increase adverse events (low-quality evidence). High- to moderate-quality evidence suggests increased adverse events with efinaconazole 10% solution or tavaborole 5% solution. We downgraded evidence for heterogeneity, lack of blinding, and small sample sizes. There is uncertainty about the effectiveness of device-based treatments, which were under-represented; 80% of studies assessed topical treatments, but we were unable to evaluate all of the currently relevant topical treatments. Future studies of topical and device-based therapies should be blinded, with patient-centred outcomes and an adequate sample size. They should specify the causative organism and directly compare treatments.

Chitosan-Based Drug Delivery Systems for Optimization of Photodynamic Therapy: a Review

Drug delivery systems (DDS) can be designed to enrich the pharmacological and therapeutic properties of several drugs. Many of the initial obstacles that impeded the clinical applications of conventional DDS have been overcome with nanotechnology-based DDS, especially those formed by chitosan (CS). CS is a linear polysaccharide obtained by the deacetylation of chitin, which has potential properties such as biocompatibility, hydrophilicity, biodegradability, non-toxicity, high bioavailability, simplicity of modification, aqueous solubility, and excellent chemical resistance. Furthermore, CS can prepare several DDS as films, gels, nanoparticles, and microparticles to improve delivery of drugs, such as photosensitizers (PS). Thus, CS-based DDS are broadly investigated for photodynamic therapy (PDT) of cancer and fungal and bacterial diseases. In PDT, a PS is activated by light of a specific wavelength, which provokes selective damage to the target tissue and its surrounding vasculature, but most PS have low water solubility and cutaneous photosensitivity impairing the clinical use of PDT. Based on this, the application of nanotechnology using chitosan-based DDS in PDT may offer great possibilities in the treatment of diseases. Therefore, this review presents numerous applications of chitosan-based DDS in order to improve the PDT for cancer and fungal and bacterial diseases.

Effects of Photodynamic Inactivation on the Growth and Antifungal Susceptibility of Rhizopus oryzae

Mucormycosis is an aggressive and high-mortality opportunistic fungal infection, especially in immunocompromised patients. Conventional antifungals or surgery showed a limited effect on this disease. The antimicrobial photodynamic therapy (aPDT) has been proven to be a promising therapeutic choice against multiple pathogenic fungi. We evaluated the effect of aPDT by using methylene blue (MB) combined with a light emitting diode (LED) on the viability of Rhizopus oryzae, as well as the antifungal susceptibility after aPDT treatment in vitro. A total of six strains were included in this study; MB (8, 16, and 32 μg/ml) was chosen for the photosensitizer, and a light source of LED (635 ± 10 nm, 12 J/cm²) device was used to active it. aPDT with MB (32 μg/ml) and LED was highly effective in cell growth inhibition and exhibited colony-forming unit reductions of up to 4.3log₁₀. The minimal inhibitory concentration ranges of itraconazole, posaconazole, and amphotericin B decreased from > 32 μg/ml to 4-8 μg/ml, 8-16 μg/ml to 0.5-2 μg/ml, and 2-4 μg/ml to 0.25-0.5 μg/ml, respectively, after pre-treatment with MB (8 μg/ml) and LED. In conclusion, aPDT with MB and LED was a promising therapeutic option against R. oryzae infections alone or combined with antifungal agents. However, further investigation is needed to determine the potential for clinic therapy and to elucidate the underlying mechanism.

Global perspectives for the management of onychomycosis

Onychomycosis is a fungal nail infection caused by dermatophytes, nondermatophyte molds, and yeasts. This difficult-to-treat chronic infection has a tendency to relapse despite treatment. This paper aims to offer a global perspective on onychomycosis management from expert physicians from around the world. Overall, the majority of experts surveyed used systemic, topical, and combination treatments approved in their countries and monitored patients based on the product insert or government recommendations. Although the basics of treating onychomycosis were similar between countries, slight differences in onychomycosis management between countries were found. These differences were mainly due to different approaches to adjunctive therapy, rating the severity of disease and use of prophylaxis treatment. A global perspective on the treatment of onychomycosis provides a framework of success for the committed clinician with appreciation of how onychomycosis is managed worldwide.

Therapy of Skin, Hair and Nail Fungal Infections

Treatment of superficial fungal infections has come a long way. This has, in part, been through the development and evaluation of new drugs. However, utilising new strategies, such as identifying variation between different species in responsiveness, e.g., in tinea capitis, as well as seeking better ways of ensuring adequate concentrations of drug in the skin or nail, and combining different treatment methods, have played equally important roles in ensuring steady improvements in the results of treatment. Yet there are still areas where we look for improvement, such as better remission and cure rates in fungal nail disease, and the development of effective community treatment programmes to address endemic scalp ringworm.

Onychomycosis: Treatment and prevention of recurrence

Onychomycosis is a fungal nail infection caused by dermatophytes, nondermatophytes, and yeast, and is the most common nail disorder seen in clinical practice. It is an important problem because it may cause local pain, paresthesias, difficulties performing activities of daily living, and impair social interactions. The epidemiology, risk factors, and clinical presentation and diagnosis of onychomycosis were discussed in the first article in this continuing medical education series. In this article, we review the prognosis and response to onychomycosis treatment, medications for onychomycosis that have been approved by the US Food and Drug Administration, and off-label therapies and devices. Methods to prevent onychomycosis recurrences and emerging therapies are also described.

Antifungal photodynamic inactivation against dermatophyte Trichophyton rubrum using nanoparticle-based hybrid photosensitizers

Trichophyton rubrum is one of the most common dermatophytes, which can cause fungal nail and ringworm infections. Infections associated with T. rubrum have become a global phenomenon. Herein, we report the antifungal photodynamic inactivation of T. rubrum (ATCC 28188) using the mesoporous silica-coated silver nanoparticle-based hybrid photosensitizers without involving antifungal drugs. Results show that the hybrid photosensitizers display low cytotoxicity under the experimental conditions where significant killing (∼3 orders of magnitude) against T. rubrum is observed. These results demonstrate the potential applications of the nanoparticle-based hybrid photosensitizers in antifungal photodynamic therapy against T. rubrum.

Effects of Photodynamic Therapy on the Growth and Antifungal Susceptibility of Scedosporium and Lomentospora spp

Scedosporium and Lomentospora species are the second most frequent colonizing, allergenic, or invasive fungal pathogens in patients with cystic fibrosis, and are responsible for infections varying from cutaneous and subcutaneous tissue infections caused by traumatic inoculation to severe systemic diseases in immunocompromised patients. The clinical relevance of fungal airway colonization for individual patients harboring Scedosporium and Lomentospora species is still an underestimated issue. The high resistance of Scedosporium and Lomentospora species to antifungal drugs has highlighted the need for alternative treatment modalities, and antimicrobial photodynamic therapy may be one such alternative. In this study, methylene blue was applied as a photosensitizing agent to 6 type strains of Scedosporium and Lomentospora species, and we irradiated the strains using a light-emitting diode (635 ± 10 nm, 12 J/cm²). We evaluated the effects of photodynamic therapy on strain growth and on the in vitro susceptibility of the strains to itraconazole, voriconazole, posaconazole, and amphotericin B. A colony-forming unit reduction of up to 5.2 log₁₀ was achieved. Minimal inhibitory concentration ranges also decreased significantly with photoinactivation. Photodynamic therapy improved both the inactivation rates and the antifungal susceptibility profile of all fungal isolates tested.

Onychomycosis in the 21st Century: An Update on Diagnosis, Epidemiology, and Treatment

Onychomycosis accounts for 50% of all nail disease cases and is commonly caused by dermatophytes. Diabetes, human immunodeficiency virus, immunosuppression, obesity, smoking, and advancing age are predisposing factors of this fungal infection. Potassium hydroxide and culture are considered the current standard for diagnosing onychomycosis, revealing both fungal viability and species identification. Other diagnostic tests currently available include periodic acid-Schiff staining, polymerase chain reaction techniques, and fluorescent staining. Across 6 recently published epidemiology studies, the global prevalence of onychomycosis was estimated to be 5.5%, falling within the range of previously reported estimates (2%-8%). Newly approved onychomycosis treatments include efinaconazole, tavaborole, and laser therapy with lasers only approved to temporarily increase the amount of clear nail. Additional onychomycosis treatments being investigated include iontophoresis and photodynamic therapy with small open-label studies reported thus far. Preventative strategies, to help decrease recurrence and reinfection rates, include sanitisation of footwear and prophylactic topical antifungal agents.

Methylene Blue for the Treatment of Intractable Pain Associated with Oral Mucositis

Oral mucositis is a common and often debilitating complication among cancer patients receiving radiation therapy to the head and neck or chemotherapy agents, or undergoing hematopoietic stem cell transplantation. Pain and decreased oral function associated with oral mucositis may persist long after the conclusion of therapy. Although most patients respond to conservative management, a subset of patients develops intractable pain with severe consequences. For some, the use of total parenteral nutrition with insertion of percutaneous endoscopic gastrostomy feeding tubes is the only alternative. Current recommendations to treat mucositis and its related pain include basic oral care, bland oral rinses, topical anesthetics, and systemic analgesics. We believe that chemical neurolysis of the affected areas with methylene blue used as an oral rinse is a noninvasive, efficient, safe, and cost-effective alternative that can provide prolonged analgesia in patients with intractable pain of oral mucositis. The benefits of this therapy are reflected in its improvement of patients' quality of life by enabling oral feeding and controlling pain. We report a series of 5 consecutive patients with intractable oral mucositis-related pain despite conventional treatment with systemic opiates. All 5 patients responded well to the use of 0.05% methylene blue as mouth rinse, demonstrating sustained analgesia over 3 weeks. The treatment was tolerated well, and overall patient satisfaction was very high. We also observed that methylene blue rinse significantly reduced the total opioid requirement, as demonstrated by reductions in the patients' morphine equivalent daily dose scores after its use. Our case series suggests that 0.5% methylene blue oral rinse therapy is an effective and inexpensive modality that can be used safely to palliate intractable oral pain in patients with mucositis associated with cancer treatment. To our knowledge, this is the first report using this therapy to treat pain from oral mucositis.

Photodynamic Therapy and Skin Appendage Disorders: A Review

Photodynamic therapy (PDT) is a noninvasive treatment that utilizes light treatment along with application of a photosensitizing agent. In dermatology, PDT is commonly used and approved for the treatment of oncological conditions such as actinic keratosis, Bowen disease and superficial basal cell carcinoma. In the last 2 decades however, PDT has also been used for the treatment of several nonneoplastic dermatological diseases. The present review summarizes published data on PDT application in skin appendage disorders. Our literature review shows that: (a) PDT may be a suitable treatment for acne, folliculitis decalvans, hidradenitis suppurativa, nail diseases, and sebaceous hyperplasia; (b) there is a lack of agreement on PDT features (type, concentrations and incubation period of used substances, number and frequency of PDT sessions, optimal parameters of light sources, and patient characteristics [e.g., failure to previous treatments, disease severity, body surface area involved, etc.] which should guide PDT use in these diseases);

Methyl aminolevulinate photodynamic therapy for onychomycosis: a multicentre, randomized, controlled clinical trial

BACKGROUND

Onychomycosis is a common fungal nail infection that responds poorly to antifungals.

OBJECTIVE

To investigate the efficacy and safety of methyl aminolevulinate (MAL) photodynamic therapy (PDT) in the treatment of onychomycosis.

METHODS

A multicentre (3), randomized, placebo-controlled clinical trial compared the effects of three sessions of urea (40%) plus conventional MAL-PDT with urea (40%) plus placebo (red light) photodynamic therapy (pPDT) in onychomycosis patients. Efficacy, both clinical (onychomycosis severity index, OSI) and microbiological, was blindly evaluated after 36 weeks of follow-up.

RESULTS

Forty patients were analysed in the trial. Twenty-two received MAL-PDT and 18 pPDT. A complete response (OSI = 0) was observed for four patients (18.18%) in the MAL-PDT group and one (5.56%) in the pPDT group (NTT 7.92, 95% CI: 2.98-9.69, P = 0.23). A decrease in OSI score of over 75% (OSI75) was achieved by 40.91% of the patients in the MAL-PDT group and 16.67% in the pPDT group (P = 0.096). Microbiological cure was achieved by seven patients (31.82%) in the MAL-PDT group and two (11.11%) in the pPDT group (P = 0.178). MAL-PDT resulted in better rates of clinical response [OSI >75%: 53.85% vs. 18.75% (P =0.048)] and microbiological cure [41.56% vs. 7.14% (P = 0.037)] in non-dystrophic vs. dystrophic onychomycosis patients. No significant side-effects were reported. The limitations of the study were the reduced sample size and the unexpected efficacy of the control treatment, which was attributed to the 40% urea pre-treatment.

CONCLUSION

This study did not show significant differences between urea 40% + MAL-PDT and urea 40% + pPDT in the treatment of onychomycosis. However, some results suggest that this treatment may constitute an alternative for dermatophyte and non-dermatophyte mould onychomycosis in patients not eligible for systemic treatment, particularly in the absence of total nail dystrophy.

Photodynamic therapy for onychomycosis: A systematic review

Other than a cosmetic concern, Onychomycosis is also a prevalent nail disease, which is extremely difficult to treat, and sometimes is refractory to conventional therapy. Moreover, many patients are not eligible to take oral antifungals owing to polypharmacy and comorbidities. Systemic side effects seen with oral antifungals have lead to patient nonadherence and adverse events. Therefore, newer therapies are being investigated for onychomycosis that would be free of systemic complications posed by oral therapy. Photodynamic therapy (PDT) is one of those being currently studied, which involves the use of photosensitizer and a light source to excite the photosensitizer to generate reactive oxygen species. The present review will put some light on PDT as an upcoming treatment modality for onychomycosis. We performed a systematic review of the literature to find the articles relevant to the use of PDT for onychomycosis. From the primary search of 43 articles, 17 papers are included in this review.

Evaluation of the Effects of Photodynamic Therapy Alone and Combined with Standard Antifungal Therapy on Planktonic Cells and Biofilms of Fusarium spp. and Exophiala spp

Infections of Fusarium spp. and Exophiala spp. are often chronic, recalcitrant, resulting in significant morbidity, causing discomfort, disfigurement, social isolation. Systemic disseminations happen in compromised patients, which are often refractory to available antifungal therapies and thereby lead to death. The antimicrobial photodynamic therapy (aPDT) has been demonstrated to effectively inactivate multiple pathogenic fungi and is considered as a promising alternative treatment for mycoses. In the present study, we applied methylene blue (8, 16, and 32 μg/ml) as a photosensitizing agent and light emitting diode (635 ± 10 nm, 12 and 24 J/cm²), and evaluated the effects of photodynamic inactivation on five strains of Fusarium spp. and five strains of Exophiala spp., as well as photodynamic effects on in vitro susceptibility to itraconazole, voriconazole, posaconazole and amphotericin B, both planktonic and biofilm forms. Photodynamic therapy was efficient in reducing the growth of all strains tested, exhibiting colony forming unit-reductions of up to 6.4 log₁₀ and 5.6 log₁₀ against planktonic cultures and biofilms, respectively. However, biofilms were less sensitive since the irradiation time was twice longer than that of planktonic cultures. Notably, the photodynamic effects against Fusarium strains with high minimal inhibitory concentration (MIC) values of ≥16, 4-8, 4-8, and 2-4 μg/ml for itraconazole, voriconazole, posaconazole and amphotericin B, respectively, were comparable or even superior to Exophiala spp., despite Exophiala spp. showed relatively better antifungal susceptibility profile. MIC ranges against planktonic cells of both species were up to 64 times lower after aPDT treatment. Biofilms of both species showed high sessile MIC50 (SMIC50) and SMIC80 of ≥16 μg/ml for all azoles tested and variable susceptibilities to amphotericin B, with SMIC ranging between 1 and 16 μg/ml. Biofilms subjected to aPDT exhibited a distinct reduction in SMIC50 and SMIC80 compared to untreated groups for both species, except SMIC80 of itraconazole against Fusarium biofilms. In conclusion, in vitro photodynamic therapy was efficient in inactivation of Fusarium spp. and Exophiala spp., both planktonic cultures and biofilms. In addition, the combination of aPDT and antifungal drugs represents an attractive alternative to the current antifungal strategies. However, further investigations are warranted for the reliable and safe application in clinical practice.