SEARCH

SEARCH BY CITATION

Keywords:

  • nail disease;
  • photochemotherapy;
  • treatments

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. References

Photodynamic therapy (PDT) is a medical modality that uses a combination of visible light and a photosensitive compound in the presence of oxygen. It is widely used to treat non-melanoma skin cancer; other indications are being investigated, especially onychomycosis. Eighty patients with toenail onychomycosis were enrolled and completed this randomized, parallel, placebo-controlled study. For 24 weeks, 40 patients (Group A) were treated with one placebo capsule per week and sessions of 2% methylene blue aqueous solution irradiated with light emission diode device (MBLED/PDT) with 18 J/cm2; and another 40 patients (Group B) were treated with 300 mg oral fluconazole per week and sessions of placebo PDT (haematoxylin-diluted 1 : 10). The use of MBLED/PDT consisted of sessions with an interval of 15 days between each session for 6 months. Microbiological and clinical cure was assessed at 1 and 12 months posttreatment. Group A (MBLED/PDT) patients showed a significant response (p < 0.002) compared with Group B (fluconazole), especially in patients who required nail abrasion (p < 0.001). The MBLED/PDT is safe, effective, and well tolerated; it promotes a favorable outcome with good patient adherence and may be considered as a practical and feasible treatment option for toenail onychomycosis.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. References

Onychomycosis, a type of superficial mycosis, is extremely difficult to manage. Owing to the slow growth of nails, medication must be used over a long period, resulting in low cure rates and frequent relapses. Since the introduction of azole drugs to treat onychomycosis, there has been great demand for new drugs; and studies have been conducted to determine the optimum therapeutic regimen [1, 2]. Surgical techniques such as dermabrasion and chemical exfoliation as complementary adjuncts to standard topical and oral antifungal treatment are underutilized [3]. Methylene blue (MB), a molecule that has played an important role in microbiology and pharmacology, is well known as a histological stain, for which it has been used for many years [4]. Dermal exposure to MB has no reported side effects aside from photosensitivity [5]. This class of dyes exhibits intense absorption at wavelengths of 600–660 nm, corresponding to the region of red light. Photodynamic therapy (PDT) is a noninvasive treatment for onychomycosis, which selectively destroys infectious pathogens [6]. Studies have demonstrated that MB light emission diode/PDT (MBLED/PDT) is effective and safe, with response rates of approximately 85–100% [7, 8]. A light source output intensity of greater than 1800 mW/cm2 is required to effectively combat superficial mycosis [9]. We conducted a clinical study to evaluate the efficacy of the MBLED/PDT compared with fluconazole in patients with toenail onychomycosis.

Patients and methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. References

The present study was a randomized, parallel, stratified, placebo-controlled, single-blind, longitudinal trial that included patients with distal and lateral subungual toenail onychomycosis diagnosed clinically and mycologically. Inclusion criteria were clinical signs of onychomycosis (e.g., discoloration, dystrophy of the nail plate, subungual debris, or onycholysis) confirmed by direct microscopic examinations of the subungual material with 20% potassium hydroxide; or by culture using Sabouraud agar with chloramphenicol and cycloheximide, and Sabouraud glucose agar. The patients with positive mycology and also the patients with positive microscopy and negative culture were investigated. The following subjects were excluded: those with nail changes because of skin disease or associated systemic diseases; pregnant or lactating women; and those who were allergic to fluconazole or had previously used antifungal medications.

These patients were 18–85 years old (Table 1). Based on the results of a previous study, they were included in chronological order and randomly divided into two groups (A and B) [8]. For 24 weeks, group A (MBLED/PDT) received one placebo capsule per week and sessions of PDT. For 24 weeks, group B received 300 mg oral fluconazole per week and sessions of placebo PDT (hematoxylin diluted 1 : 10).

Table 1. Baseline demographics, disease characteristics and patient flow
 Group AGroup B
n = 70n = 72
  1. a

    Combination of direct microscopy and culture results.

  2. Group A, methylene blue light emission diode/photodynamic therapy; Group B, fluconazole.

Gender, n(%)  
Male42(60)39(54.2)
Female28(40)33(45.8)
Age, years  
Mean ± SD57±12.849.8±10.8
Number of affected nails  
Mean ± SD4.7±1.24.9±1.6
Mycological examination positivea, n(%)46(65.7)49(68.1)
Causative organisms, n(%)  
Trichophyton rubrum24(34.3)28(38.9)
Trichophyton mentagrophytes6(8.6)5(10.2)
Epidermophyton floccosum1(1.3)0(0)
Aspergillus niger1(1.4)1(1.4)
Candida sp9(12.9)11(15.2)
Fusarium1(1.4)0(0)
Missing28(40)27(37.5)
Patient flow – withdrawn, n (%)  
Mycological examination negative24(34.3)23(31.9)
Lack of efficacy1(1.4)5(6.9)
Patient request3(4.3)1(1.4)
Lost to follow-up2(2.9)3(4.2)
Patient flow – completed the study, n(%)40(57.1)40(55.6)

The use of PDT consisted of sessions of MBLED with an interval of 15 days between each session for 6 months. The 2% MB aqueous solution was applied to the lesion until saturation occurred, followed by a rest period of 3 minutes. The MB solution was not washed off. After the rest period, the lesion was immediately illuminated with noncoherent red light (630 nm, 18 J/cm2) from a LED device with a light intensity output of 3100 mW/cm2 and optical intensity of 100 mW/cm2 (Multiwaves®, Industra, São Carlos, Brazil). Each group consisted of some patients who required nail abrasion. Patients with hyperkeratotic lesions (hyperkeratosis of the nail plate greater than 2 mm), fungal longitudinal streaks, or dermatophytomas were subjected to nail abrasion using a rotation abrasive device with a 3-mm diamond tip (Dermoabrasor, Bleymed®, Curitiba, Brazil) to remove scales and crusts in order to facilitate penetration of the 2% MB aqueous solution.

Patients were evaluated at the beginning of therapy and at 4-week intervals over the 6-month treatment period, and then at the third-, sixth-, and 12th-month posttreatment. Clinical cure was defined as complete replacement of the mycotic nail bed and dystrophic nail plate in a eutrophic nail. Microbiological and clinical cure was assessed at 1 and 12 months posttreatment. Safety was assessed through adverse events and laboratory monitoring. The data were described using means and standard deviations (SD). Statistical analysis was performed using percentages and Fisher's exact test. The nature of the present study was clearly explained to the patients, and they signed a written consent form before participation. The present study was conducted in accordance with the ethical guidelines of the Declaration of Helsinki and approved by the Ethics Committee of the Montes Claros State University.

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. References

The present authors evaluated 142 patients with clinical signs suggestive of onychomycosis. In total, 95 patients satisfied the inclusion criteria, of which 80 agreed to participate and completed the study. They were randomly divided into two groups (A and B), each with 40 patients. Group A (MBLED/ PDT) patients showed a significant response, with a clinical cure rate of 90% (FIG. 1). This study demonstrated that differences in efficacy between MBLED/PDT and fluconazole were statistically significant (p < 0.002). Group B (fluconazole) patients responded poorly, especially those who required nail abrasion (Table 2). After 12 months of posttreatment follow-up, the clinical cure rate in group A reduced to 80% (patients with and without nail abrasion).

figure

Figure 1. Toenail onychomycosis treated with photodynamic therapy based on methylene blue dye. (A) Before treatment; (B) 3 months; (C) 6 months; (D) rotation abrasive device with a 3-mm diamond tip. *Presence of fungal longitudinal streaks and poor therapeutic response.

Download figure to PowerPoint

Table 2. Comparative evaluation of photodynamic therapy based on methylene blue dye and fluconazole for toenail onychomycosis treatment
Week of follow-upNo. of patients showing clinical and mycological cure
Group A (MBLED/PDT)Group B (fluconazole)
Nail abrasion n (%)Nail abrasion n (%)
Realized 18 (100)Unrealized 22 (100)Realized 18 (100)Unrealized 22 (100) (100)
  1. ap = 0.026, Fisher's exact test; bp = 0.001, Fisher's exact test; cp = 0.002, Fisher's exact test; dPatients were treated with methylene blue light emission diode/photodynamic therapy(MBLED/PDT).

  2. Realized, presence of dermatophytoma, fungal longitudinal streaks or subungual hyperkeratosis >2 mm; Unrealized, absence of dermatophytoma, fungal longitudinal streaks or subungual hyperkeratosis >2 mm.

Treatment    
Week 40(0)0(0)0(0)0(0)
Week 80(0)1(4.5)0(0)0(0)
Week 124(22.2)15(68.2)a0(0)7(31.8)a
Week 167(31.8)19(83.4)1(5.6)9(40.9)
Week 2011(61.1)21(95.5)2(11.1)12(54.5)
Week 2414(77.8)b22(100)c4(22.2)b14(63.6)c
After treatment    
Week 1214(77.8)22(100)_d14(63.6)
Week 2414(77.8)22(100)_d12(54.5)
Week 4812(66.7)20(90.1)_d10(45.6)

None of the patients receiving MBLED/PDT (group A) experienced systemic adverse events or phototoxicity reactions. One patient with a perilesional cleft presented side effects such as pain and burning. In the group treated with 300 mg oral fluconazole per week, two patients showed mild symptoms of dyspepsia, which did not require suspension of treatment during the study period.

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. References

This comparative study of MBLED/PDT and systemic fluconazole showed that both were effective in the treatment of toenail onychomycosis. Moreover, fluconazole, at these doses and treatment durations, was the least effective. The treatment duration (6 months) was the main limitation of this study, which reduced the success rate in patients who underwent nail abrasion and in the fluconazole group. The length of treatment also reduced patient compliance in fluconazole group. PDT with MB for the treatment of cutaneous fungal infections (athlete's foot, thrush) has been used for several decades [8, 9]. Previous studies with this modality showed low efficacy because rather than the MB absorption band of 600–660 nm (red), light sources in the blue spectrum (420 nm) were used over a long exposure time sometimes exceeding 60 minutes [9, 10]. Studies using macrocyclic molecules, which allowed only a few sessions (3 on average) because of the high cost, a low clinical cure rate probably resulted from the inadequate number of sessions [11, 12]. Group A (MBLED/PDT) achieved a clinical cure rate of 90%, rate higher than another study [8], probably because of use of surgical abrasion for hyperkeratotic lesions, dermatophytoma, and fungal longitudinal streaks, which are determinants of treatment failure [13, 14]. Another study showed that the fungicidal activity of PDT can be enhanced by increasing the energy density, which might reduce the number of sessions and the treatment duration [15].

In conclusion, onychomycosis remains a therapeutic challenge, mainly because daily or weekly maximum levels of antifungal drug administration must be sustained over a lengthy treatment period. The results of this study confirm previous clinical study: MBLED/PDT is safe, effective, well tolerated, and promotes a favorable outcome with good patient adherence [8]. It may be considered a practical and feasible treatment option for onychomycosis in patients who can attend a medical facility for treatment.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. References