Onychomycosis: A Review

The first case of fingernail onychomycosis due to Neoscytalidium novaehollandiae, molecular identification and antifungal susceptibility

Onychomycosis is considered a fungal nail infection caused mainly by dermatophytes, yeasts and non-dermatophyte molds including dematiaceous fungi. Onychomycosis caused by non-dermatophyte molds is a health problem in the medical environment as the patients frequently return to outpatient clinics seeking new therapeutic modalities. Here, we report the first case of onychomycosis caused by a black fungus, Neoscytalidium novaehollandiae, in the right hand finger nail of a 52-year-old Iranian female with no history of immunodeficiency and underlying disease. The pattern of nail involvement was recognized as total dystrophic onychomycosis. Examination of nail scrapings with potassium hydroxide revealed brown, septate and branching sub-hyaline to dark-colored hyphae. The black fungus isolated in culture was identified as Neoscytalidium novaehollandiae by molecular analysis. The patient received oral terbinafine plus ciclopirox nail lacquer twice a week and began responding to the treatment three months after initial antifungal therapy. Additional four weeks' use of terbinafine plus ciclopirox nail lacquer completely resolved the clinical manifestations of onychomycosis. After four months, both microscopy and culture were negative.

Auxarthron alboluteum related to non-dermatophytic toenail infection in Kurdistan region, Iraq: A case report

We report a rare case of non-dermatophytic onychomycosis of the big toenail caused by Auxarthron alboluteum in a 63-years old Iraqi female with a history of diabetes. The big toenail showed distal subungual onychomycosis with extensive yellow-white discoloration. Identification of the causative agent was confirmed by morphological and microscopical characteristics in culture and analysis of ITS-rDNA region. To the best of our knowledge, the isolated Auxarthron alboluteum reported here is a new etiologic species of nail infection in Iraq and this is the first case of its kind to be reported in the world.

Optical coherence tomography of onychomycosis: proposed terminology and a suggestion of practical usage

Onychomycosis is the most common cause of nail changes accounting for about half of all nail diseases. It is important to diagnose the fungal pathogen to prescribe adequate treatment, but as genus- and species-specific diagnostic tests can be time consuming and expensive, it is crucial to obtain representative tissue during nail scrapings. Optical coherence tomography (OCT) is a non-invasive imaging tool enabling real-time imaging of skin and tissue. Pilot studies using OCT have described morphological characteristics of onychomycosis, though diagnostic criteria of onychomycosis and other nail diseases are lacking. The aim of this study is to investigate the applicability of OCT to detect and localize fungal elements in nails with clinical signs of onychomycosis. OCT scans and nail scrapings were performed on all participants and only confirmed cases of onychomycosis were included in the data analysis. All scans were analyzed, and a set of morphological criteria based on known literature and deviations from healthy nail morphology were suggested. The suggested morphological features were: hyperreflective lines divided into sharply and diffusely demarcated; hyperreflective dots divided into singular and clustered patterns; irregular surface, divided into mild, moderate and severe degree; dark bands and disturbed architecture. The suggested OCT morphology is a refinement of previous studies, and though OCT cannot replace genus- or species-specific identification, it could be a useful assistance tool to increase diagnostic sensitivity of nail scrapings and laboratory tests as well as for monitoring treatment response.

Onychomycosis Associated with Superficial Skin Infection Due to Aspergillus sydowii in an Immunocompromised Patient

Opportunistic fungal infections of the skin and nail are frequently encountered in human. Recent years have shown increased incidence of fungal infections especially in immunocompromised patients. Onychomycosis in HIV-infected patients is reported to occur in 15-40%, four times more than in the general population. Here, we report a case of fingernail proximal subungual onychomycosis with associated skin infection caused by an opportunistic mold, Aspergillus sydowii, in a HIV positive individual. Isolation of A. sydowii from nail and skin of an immunocompromised person needs accurate identification for successful treatment.

A Week of Oral Terbinafine Pulse Regimen Every Three Months to Treat all Dermatophyte Onychomycosis

Terbinafine has proved to treat numerous fungal infections, including onychomycosis, successfully. Due to its liver metabolization and dependency on the cytochrome P450 enzyme complex, undesirable drug interaction are highly probable. Additionally to drug interactions, the treatment is long, rising the chances of the appearance of side effects and abandonment. Pharmacokinetic data suggest that terbinafine maintains a fungicidal effect within the nail up to 30 weeks after its last administration, which has aroused the possibility of a pulse therapy to reduce the side effects while treating onychomycosis. This study's goal was to evaluate the effectiveness of three different oral terbinafine regimens in treating onychomycosis due to dermatophytes. Sixty-three patients with onychomycosis were sorted by convenience in three different groups. Patients from group 1 received the conventional terbinafine dose (250 mg per day for 3 months). Group 2 received a monthly week-long pulse-therapy dose (500 mg per day for 7 days a month, for 4 months) and group 3 received a 500 mg/day dose for 7 days every 3 months, totaling four treatments. There were no statistical differences regarding the effectiveness or side effects between the groups. Conclusion: A quarterly terbinafine pulse regimen can be a possible alternative for treating onychomycosis caused by dermatophytes.

Determination of antifungal minimum inhibitory concentration and its clinical correlation among treatment failure cases of dermatophytosis

Introduction:

Dermatophytes are most common infectious agents causing superficial mycosis worldwide. A number of topical as well as systemic antifungal drugs are available for treatment of dermatophytosis. Superficial mycosis caused by dermatophytes can be easily treated by topical or oral antifungal drugs, but in the course of time, an increased number of treatment failure cases are appearing. Possible cause for treatment failure could be poor patient compliance, poor drug penetration into affected lesion, and also drug resistance in dermatophytes. The aim of this study is to investigate minimum inhibitory concentration and clinical correlation in treatment failure cases of dermatophytosis.

Methods:

Skin, hair and nail samples were collected from treatment failure cases of dermatophytosis. A total 75 isolates were tested for MIC against four antifungal drugs in the study. Fluconazole, itraconazole, ketoconazole and terbinafine were the antifungal drugs tested using broth microdilution method. MIC₅₀ and MIC₉₀ values were recorded.

Results:

A total of 75 dermatophytic isolates were tested. Dermatophytic isolates in this study were Trichophyton mentagrophytes (n = 31), T. rubrum (n = 13), T. tonsurans (n = 12), T. verrucosum (n = 9), M. gypseum (n = 5), E. floccosum (n = 4) and T. violaceum (n = 1). MIC₉₀ value for fluconazole and terbinafine was significantly higher.

Conclusion:

MIC of 17.33% isolates for fluconazole and 33.33% isolates for terbinafine were lower than cut-off value, which indicates that not all treatment failure cases are due to drug resistance.

In vitro Evaluation of Photodynamic Effects Against Biofilms of Dermatophytes Involved in Onychomycosis

Dermatophytes are the most common cause of onychomycosis, counting for 90% fungal nail infection. Although dermatophyte pathogens are normally susceptible to antifungal agents, onychomycosis often results in refractory chronic disease, and the formation of biofilms frequently underlines the inadequate responses and resistance to standard antifungal treatment. Numerous in vitro and in vivo antimicrobial photodynamic therapy (aPDT) studies have shown biofilm eradication or substantial reduction, however, such investigation has not yet been expanded to the biofilms of dermatophytes involved in onychomycosis. To shed a light on the potential application of aPDT in the clinic management of onychomycosis, in particular with the manifestation of dermatophytoma, we investigated photodynamic effects on the viabilities and the drug susceptibilities of the biofilm of dermatophytes in vitro. Here, methylene blue at the concentration of 8, 16, and 32 μg/ml applied as photosensitizing agent and LED (635 ± 10 nm, 60 J/cm²) as light source were employed against six strains of Trichophyton rubrum, ten strains of Trichophyton mentagrophytes and three strains of Microsporum gypseum isolated from clinical specimens. Our results indicated highly efficient photodynamic inhibition, exhibiting CFU (colony forming unit) reduction up to 4.6 log₁₀, 4.3 log₁₀, and 4.7 log₁₀ against the biofilms formed by T. rubrum, T. mentagrophytes, and M. gypseum, respectively. Subjected biofilms displayed considerable decreases in SMICs (sessile minimum inhibitory concentrations) to multiple antifungal agents when compared with untreated groups, indicating the biofilms of dermatophytes became more susceptible to conventional antifungal drugs after aPDT. Additionally, the obliteration of biofilm after aPDT could be observed as shattered and ruptured structures being evident in SEM (Scanning Electron Microscopy) images. These findings suggest that aPDT is an attractive alternative treatment holding great promise for combating recalcitrant onychomycosis associated with the biofilm formation.

Therapy and Antifungal Susceptibility Profile of Microsporum canis

Microsporum canis is a worldwide diffused zoophilic dermatophyte which causes clinical conditions often characterised by multifocal alopecia, scaling, and circular lesions in many animal species, including humans. A large variety of oral and topical antifungal protocols is available for treating M. canis infection. However, the efficacy of these drugs and treatment protocols is variable, with treatment failure up to 40% of patients possibly due to resistance phenomena. The lack of standardised reference methods for evaluating the antifungal susceptibility of M. canis represents a major hindrance in assessing microbiological resistance in unresponsive clinical cases. Therefore, data about conventional therapy against M. canis and the protocols employed to test the antifungal activity of the most commonly employed drugs (i.e., azoles, polyenes, allylamines, and griseofulvin) have been summarised herein. This article focuses on technical parameters used for antifungal susceptibility tests, their effects on the minimum inhibitory concentration value, as well as their clinical implications.

Daily Application of an Aqueous, Acidifying, Peelable Nail Polish versus Weekly Amorolfine for Topical Onychomycosis Treatment: A Prospective, Randomized, Blinded Trial

Introduction

Onychomycosis is a fungal nail infection, frequently caused by dermatophytes, which occurs in 2–14% of Western adults. The present study was set up to evaluate the efficacy and safety of a water-based, peelable nail polish (daily application), which acidifies the nail environment, versus a 5% amorolfine nail lacquer (weekly application) for topical treatment of mild-to-moderate onychomycosis.

Methods

One hundred two adults were randomized in this open, prospective, blinded trial. Clinical efficacy was evaluated at baseline and days 30, 60, 120, and 180, respectively. All patients underwent microbiological testing (at baseline and study end). The primary objective of this trial was the change in the percentage of healthy nail surface at day 180.

Results

The percentage of healthy surface between baseline and day 180 increased with 11.8% in the test product group and 13.2% in the amorolfine group, which were statistically comparable. Other onychomycosis-related parameters (dystrophy, discolouration, thickening, and healthy aspect, respectively) showed significant (p < 0.05) improvement after 180 days (versus baseline) with both treatments. Clinical performance was further confirmed by the frequency of patients showing onychomycosis improvement or success at the end of the study: 96.0% (test product) versus 79.6% (amorolfine). Microbiological results and improved quality of life confirmed clinical performance. Both treatments were well tolerated and appreciated for their properties and efficacy.

Conclusion

The present trial confirmed the clinical performance of daily acidification of the nail, as reflected by (1) a comparable increase of percentage of healthy nail surface following treatment with the test product versus amorolfine, (2) the overall improvement of other onychomycosis-related parameters, (3) user convenience, and (4) absence of side effects. These data indicate that daily application of an aqueous, acetic acid-based, peelable solution can be a convenient, safe, and equally effective alternative for the topical management of onychomycosis.

Trial Registration

ClinicalTrials.gov identifier; NCT03382717

Funding

Oystershell Laboratories.

Chemical and physical strategies in onychomycosis topical treatment: A review

Onychomycosis is a fungal infection of the fingernails or toenails caused by dermatophytes, nondermatophytes, moulds, and yeasts. This condition affects around 10-30% people worldwide, negatively influencing patients' quality of life, with severe outcomes in some cases. Since the nail unit acts as a barrier to exogenous substances, its physiological features hampers drug penetration, turning the onychomycosis treatment a challenge. Currently, there are several oral and topical therapies available; nevertheless, cure rates are still low and relapse rates achieves 10-53%. Also, serious side effects may be developed due to long-term treatment. In light of these facts, researchers have focused on improving topical treatments, either by modifying the vehicle or by using some physical technique to improve drug delivery trough the nail plate, hence increasing therapy effectiveness. Therefore, the aim of this paper is to explain these novel alternative approaches. First, the challenges for drug ungual penetration are presented. Then, the chemical and physical strategies developed for overcoming the barriers for drug penetration are discussed. We hope that the information gathered may be useful for the development of safer and more effective treatments for onychomycosis.

Dermoscopy as a first step in the diagnosis of onychomycosis

Introduction

Over the years, clinical studies have provided new knowledge about the dermoscopic features of the diseases of cutaneous annexes. It seems that dermoscopy has opened a new morphological dimension in the diagnosis and management of hair disorders and onychopathies.

Aim

To identify and describe dermoscopic features of onychomycosis.

Material and methods

A total of 81 consecutive patients with onychomycosis (55 men and 26 women) were prospectively enrolled in the present study. For each patient, all fingernails and toenails were evaluated in clinical and dermoscopic examinations. Mycological tests were performed by potassium hydroxide (KOH) preparation. Mann-Whitney U and χ² tests were used for the statistical analysis, with a significance threshold of p < 0.05.

Results

Dermoscopic examination of the patients' nails revealed the following: jagged proximal edge with spikes of the onycholytic area (51.9%), longitudinal streaks and patches (44.4%), subungual hyperkeratosis (27.2%), brown-black pigmentation (9.9%) and leukonychia (1.2%). Jagged proximal edge, subungual hyperkeratosis and leukonychia were positively associated with the onychomycosis type.

Conclusions

Onychomycosis accounts for up to 50% of all consultations for onychopathies. Fast and effective diagnostic approaches are needed in everyday clinical practice. Dermoscopy can provide immediate and accurate information in the diagnosis of onychomycosis. We suggest that dermoscopy should be taken as a first step toward the diagnosis of onychomycosis.

COMBINATION ANTIFUNGAL THERAPY FOR ONYCHOMYCOSIS

Onychomycosis is a fungal infection of the nail unit including the nail matrix, the nail bed and the nail plate by both dermatophyte and non-dermatophyte agents. It is disturbs not only cosmetic disfigurement, but also it may have an impact on patients’ emotional, social and occupational functioning, finally affecting the overall quality of life. The incidence rate tends to increase, management of onychomycosis is still challenging. Important problems regarding antifungal monotherapy have experienced many failures and recurrences. In general, pharmacological approaches for onychomycosis can be topical or oral antifungal. Antifungal monotherapies often lead to failure treatment, also high incidence of recurrence. One strategy for this problem is a combination antifungal therapy. In vitro studies show the synergistic effect of using combination two antifungals (both oral antifungal or combination topical and oral antifungal), hence it is mycologically or clinically expected to increase the success rate of onychomycosis therapy. This review tries to evaluate the previous study exploring the effectiveness of antifungal combination therapies on onychomycosis. Two oral antifungals usually used are terbinafine as fungicidal agent and itraconazole as fungistatic agent. There is combination between topical and oral antifungal such as itraconazole or terbinafine with amorolfine or ciclopirox, also other combination like griseofulvin and amorolfone or tioconazole. All the combination therapies show better result than monotherapy alone, but it is still difficult to conclude whether antifungal combinations in onychomycosis will increase effectiveness due to variations in therapeutic duration, result definition, and statistical evaluation on existing studies. Further research is required with longer duration of observation, uniform patient criteria and definition of success, random control and blinding to minimize bias.

Onychomycosis due to dermatophytes species in Iran: Prevalence rates, causative agents, predisposing factors and diagnosis based on microscopic morphometric findings

OBJECTIVE

Onychomycosis (OM) or fungal nail infection is one of the most common fungal infections, which is increasingly prevalent. OM is caused by dermatophytes spp, yeasts and non-dermatophyte moulds (NDMs). The purpose of this study was to identify and determine the prevalence rates, predisposing factors and causative agents of OM using clinical symptoms and microscopic morphometric findings.

MATERIALS AND METHODS

In the present study, 180 patients suspected of OM were evaluated by direct microscopy using KOH 20%, culturing in Mycosel and Sabouraud dextrose agar media and Olysia software for identifying the causative fungi of OM.

RESULTS

From 180 referred patients, 118 (65.56%) had OM, of whom 79 (66.94%) were positive for infection with dermatophytes spp. Of the 79 cases, the commonest age group was 61-70 years (21%) with males being 46 (58.23%) and females being 33 (41.77%). Both the fingernail and toenail infections were most prevalent in male patients. Sex, diabetes and age above 60 years were significant predisposing factors for OM development. DLSO was observed as the only clinical pattern of OM and T. rubrum was the commonest dermatophyte isolate (49.34%).

CONCLUSION

This study showed that T. rubrum was the most common dermatophyte agent of OM in Iran.

Patient-reported outcomes from two randomised studies comparing once-weekly application of amorolfine 5% nail lacquer to other methods of topical treatment in distal and lateral subungual onychomycosis

Patient adherence is a key consideration in the choice of a topical regimen for the treatment of onychomycosis. The objective of this study was to investigate patient-reported outcomes (treatment utilisation, adherence and satisfaction) in onychomycosis treated with once-weekly amorolfine 5% nail lacquer versus once-daily ciclopirox 8% nail lacquer (Study A) or once-daily urea 40% ointment/bifonazole 1% cream combination regimen (Study B). Study A: Subjects received amorolfine and ciclopirox on opposite feet for 12 weeks. Study B: Subjects received amorolfine and urea/bifonazole on opposite feet for 6-7 weeks. Assessments included subject adherence as per label, treatment preference and questionnaire. Study A: More subjects adhered to amorolfine (85%) than to ciclopirox (60%) (P = .025). Overall, subjects were satisfied (95% vs 100%, respectively) and the treatments were balanced in terms of preference (50% vs 45%) at week 12. Study B: More subjects adhered to amorolfine dosage (81.8%) than to the dosage of the urea/bifonazole combination regimen (59.1%) (P = .096). At the end of study, 85.7% of subjects preferred amorolfine versus 14.3% for urea/bifonazole. Fewer subjects experienced local side effects with amorolfine (4.5%) compared to urea (27.3%) and bifonazole (15%). Amorolfine 5% nail lacquer offers a simple and convenient treatment option, which may result in improved patient adherence and consequently lead to improved efficacy and patient satisfaction.

Point-of-Care Diagnosis of Onychomycosis by Dermoscopy

BACKGROUND

Onychomycosis is one of the most common diseases of the toenails. The costs of diagnosis and treatment are substantial, and as the population ages, the overall cost burden will continue to escalate. The purpose of this study was to correlate dermoscopic features with pathologic diagnosis to support the accuracy of point-of-care diagnosis by dermoscopic examination.

METHODS

Nail unit pathology reports of 52 patients with abnormal great toenails were compared with the dermoscopic features detected by nail unit dermoscopy.

RESULTS

The dermoscopic analysis predicted the laboratory diagnosis in 90.4% of the study patients. The specific dermoscopic findings of short spikes (P < .001), long striae (P < .001), aurora borealis (P < .001), irregular termination (P = .003), dermatophytoma (P = .011), transverse onycholysis (P = .018), and dry scale (P = .04) patterns were all significantly associated with pathology test results consistent with oncyhomycosis. Transverse onycholysis (P = .018) was significantly associated with negative pathology results consistent with the diagnosis of nail dystrophy.

CONCLUSIONS

Point-of-care examination by dermoscopy positively correlates with histopathologic tests and could be used to diagnose onychomycosis while reducing diagnostic costs.

Molecular Identification and Antifungal Susceptibility Patterns of Clinical Dermatophytes Following CLSI and EUCAST Guidelines

Dermatophytes are associated with superficial infections in humans worldwide. The aim of the present study was to determine the species distribution and susceptibility patterns of clinical dermatophytes. Samples received for routine mycological processing from 124 suspected cases attending a dermatologic clinic in a tertiary care hospital were included in the study. On direct microscopy, 74.1% (92/124) were positive and 53.2% (66/124) grew on culture. The isolates were comprised of Trichophytoninterdigitale (56%) followed by Trichophytontonsurans (25.7%), Trichophytonrubrum (7.5%), Trichophytonviolaceum (4.5%), Microsporumgypseum (4.5%), and Trichophytonverrucosum (1.5%). Conventional mycological identification was concordant with ITS sequencing except for T.mentagrophytes. High minimum inhibitory concentration (MIC) values (geometric mean, >1 µg/mL) were observed for T.tonsurans and T.rubrum to terbinafine and griseofulvin. This study highlights the shift in epidemiology from T.rubrum to T.interdigitale. It also raises a concern of high MICs of terbinafine and griseofulvin among our isolates. Surveillance of antifungal susceptibility patterns can provide clinicians with local MIC data that can further aid in guiding better management in relapse cases of dermatomycosis.

Production of Fusaric Acid by Fusarium spp. in Pure Culture and in Solid Medium Co-Cultures

The ability of fungi isolated from nails of patients suffering from onychomycosis to induce de novo production of bioactive compounds in co-culture was examined. Comparison between the metabolite profiles produced by Sarocladium strictum, by Fusarium oxysporum, and by these two species in co-culture revealed de novo induction of fusaric acid based on HRMS. Structure confirmation of this toxin, using sensitive microflow NMR, required only three 9-cm Petri dishes of fungal culture. A targeted metabolomics study based on UHPLC-HRMS confirmed that the production of fusaric acid was strain-dependent. Furthermore, the detected toxin levels suggested that onychomycosis-associated fungal strains of the F. oxysporum and F. fujikuroi species complexes are much more frequently producing fusaric acid, and in higher amount, than strains of the F. solani species complex. Fusarium strains producing no significant amounts of this compound in pure culture, were shown to de novo produce that compound when grown in co-culture. The role of fusaric acid in fungal virulence and defense is discussed.