Onychomycosis: Correlation between the dermoscopic patterns and fungal culture

Preparation, Physicochemical Characterization, and Stability Study of Lippia origanoides Essential Oil-based Nanoemulsion as a Topical Delivery System

INTRODUCTION

Fungal diseases are a priority in research, development, and health care, according to the WHO, mainly due to Candida spp. Essential oils (EOs) of the genus Lippia have demonstrated broad antimicrobial biological activity. Previous studies identified the anti-Candida potential of a thymol/p-cymene chemotype EO from Lippia origanoides H.B.K coded "0018". Nanoemulsions favor the biological activity of EOs and overcome limitations such as low solubility, instability against oxidizing agents, pH, light, and low permeability. To develop, characterize, and adjust a prototype of an O/W nanoemulsion containing the "0018" EO from Lippia origanoides for its evaluation in an in vitro permeability study.

METHODS

Nanoemulsions were obtained using a high energy high shear method. Their particle size distribution, Z potential, viscosity, pH, encapsulation efficiency (EE), thermodynamic stability and the Turbiscan Stability Index (TSI) were evaluated. The nanoemulsion prototype was adjusted to improve performance characteristics and microbiological efficacy. Thymol was used as an analyte in the EO quantification using UHPLC-DAD.

RESULTS

An O/W nanoemulsion with hydrodynamic diameter <200 nm and polydispersity index <0.3, EE >95%, with TSI < 1.5, anti-Candida albicans efficiency >95% was obtained; permeable with a flow of 6.0264 μg/cm2/h and permeability coefficient of 1.3170x10-3 cm/h.

CONCLUSION

A pharmaceutical formulation prototype is obtained that maintains the physical and physicochemical characteristics over time. Permeability is verified in an in-vitro model. It is proposed to evaluate its antifungal activity in preclinical or clinical studies as a contribution to the treatment of topical fungal diseases caused by Candida spp., through the use of biological resources and Colombian biodiversity.

Promising onychomycosis treatment with hypericin-mediated photodynamic therapy: case reports

BACKGROUND

Onychomycosis (OM) is a common nail plate disorder caused by dermatophyte molds, yeasts, and non-dermatophyte molds, which use keratin in the nail plate as an energy source. OM is characterized by dyschromia, increased nail thickness, subungual hyperkeratosis, and onychodystrophy, and is typically treated with conventional antifungals despite frequent reports of toxicity, fungal resistance, and OM recurrence. Photodynamic therapy (PDT) with hypericin (Hyp) as a photosensitizer (PS) stands out as a promising therapeutic modality. When excited by a specific wavelength of light and in the presence of oxygen, to lead to photochemical and photobiological reactions on the selected targets.

METHODS

OM diagnosis was made in three suspected cases, and the causative agents were identified by classical and molecular methods, and confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). Susceptibility of planktonic cells of the clinical isolates to conventional antifungals and PDT-Hyp was evaluated, and photoacoustic spectroscopy (PAS) of Hyp permeation in nail fragments ex vivo was analyzed. Furthermore, the patients opted to undergo PDT-Hyp treatment and were subsequently followed up. The protocol was approved by the human ethics committee (CAAE, number 14107419.4.0000.0104).

RESULTS

The etiological agents of OM in patients ID 01 and ID 02 belonged to the Fusarium solani species complex, being identified as Fusarium keratoplasticum (CMRP 5514) and Fusarium solani (CMRP 5515), respectively. For patient ID 03, the OM agent was identified as Trichophyton rubrum (CMRP 5516). PDT-Hyp demonstrated a fungicidal effect in vitro, with reductions of ≥3 log₁₀ (p<0.0051 and p<0.0001), and the PAS analyses indicated that Hyp could completely permeate through both healthy and OM-affected nails. After four sessions of PDT-Hyp, mycological cure was observed in all three cases, and after seventh months, clinical cure was confirmed. PDT-Hyp showed satisfactory results in terms of efficacy and safety, and thus can be considered a promising therapy for the clinical treatment of OM.

Dermoscopy of Onychomycosis: A Systematic Review

INTRODUCTION

Onychomycosis represents a global burden accounting for about 50% of nail consultations. Several studies have tried to assess the dermoscopic features of onychomycosis. With the multiplication of papers, several "new" dermoscopic signs keep being added leading to some inconsistency in onychoscopic terminology.

OBJECTIVE

This study aimed to summarize the existing literature on the dermoscopic features of onychomycosis and propose a unified onychoscopic terminology.

METHODS

The literature search was performed using PubMed and Scopus databases up to October 30, 2021 to identify eligible contributions. In total, 33 records (2111 patients) were included.

RESULTS

The main dermoscopic signs of onychomycosis are "ruin appearance", "longitudinal striae" and "spikes" on the proximal margin of onycholytic areas, with a specificity of 99.38%, 83.78%, and 85.64% respectively. The "aurora borealis" sign had the highest sensitivity and specificity.

CONCLUSIONS

The current review provides a framework for issues related to the onychoscopic terminology of onychomycosis and is intended to serve as an aid for students, teachers, and researchers. We proposed a unifying terminology to describe dermoscopic signs of onychomycosis. Dermoscopic signs of onychomycosis show good specificity and are useful in distinguishing nail psoriasis, trauma, and onychomycosis. It helps differentiate fungal melanonychia from nail melanoma, nevi, and melanocytic activation.

Diagnostic accuracy of dermoscopy for onychomycosis: A systematic review

Background

Dermoscopy is a non-invasive adjuvant diagnostic tool that allows clinicians to visualize microscopic features of cutaneous disorders. Recent studies have demonstrated that dermoscopy can be used to diagnose onychomycosis. We performed this systematic review to identify the characteristic dermoscopic features of onychomycosis and understand their diagnostic utility.

Methods

We searched the Medline, Embase, Scopus, and Cochrane databases from conception until May 2021. Studies on the dermoscopic features of onychomycosis were screened. The exclusion criteria were as follows: fewer than 5 cases of onychomycosis, review articles, and studies including onychomycosis cases that were not mycologically verified. Studies on fungal melanonychia were analyzed separately. We adhered to the MOOSE guidelines. Independent data extraction was performed. Data were pooled using a random effects model to account for study heterogeneity. The primary outcome was the diagnostic accuracy of the dermoscopic features of onychomycosis. This was determined by pooling the sensitivity and specificity values of the dermoscopic features identified during the systematic review using the DerSimonian-Laird method. Meta-DiSc version 1.4 and Review Manager 5.4.1 were used to calculate these values.

Results

We analyzed 19 articles on 1693 cases of onychomycosis and 5 articles on 148 cases of fungal melanonychia. Commonly reported dermoscopic features of onychomycosis were spikes or spiked pattern (509, 30.1%), jagged or spiked edges or jagged edge with spikes (188, 11.1%), jagged proximal edge (175, 10.3%), subungual hyperkeratosis (131, 7.7%), ruins appearance, aspect or pattern (573, 33.8%), and longitudinal striae (929, 54.9%). Commonly reported features of fungal melanonychia included multicolor (101, 68.2%), non-longitudinal homogenous pigmentation (75, 50.7%) and longitudinal white or yellow streaks (52, 31.5%).

Conclusion

This study highlights the commonly identified dermoscopic features of onychomycosis. Recognizing such characteristic dermoscopic features of onychomycosis can assist clinicians diagnose onychomycosis by the bedside.

Dermatophytomas: Clinical Overview and Treatment

Dermatophytomas are characterized as a hyperkeratotic fungal mass in the subungual space, showing as dense white or yellow, typically in longitudinal streaks or patches. Masses can be visualized by traditional microscopy or histology. Newer technologies such as dermoscopy and optical coherence tomography also provide visual features for dermatophytoma diagnosis. The density of fungal mass, and lack of adherence to the nail structures, as well as possible biofilm development, may play a role in the reduction in drug penetration and subsequent lack of efficacy with traditional oral therapies such as terbinafine and itraconazole. A combination of drug treatment with mechanical or chemical debridement/avulsion has been recommended to increase efficacy. The topical antifungal solutions such as tavaborole, efinaconazole, and luliconazole may reach the dermatophytoma by both the transungual and subungual routes, due to low affinity for keratin and low surface tension. Current data indicates these topicals may provide efficacy for dermatophytoma treatment without debridement/avulsion. Similarly, fosravuconazole (F-RVCZ) has an improved pharmacological profile versus ravuconazole and may be an improved treatment option versus traditional oral therapies. The availability of improved treatments for dermatophytomas is crucial, as resistance to traditional therapies is on the increase.

Assessment of the Clinical Diagnosis of Onychomycosis by Dermoscopy

Background

As a common clinical superficial fungal infection, the diagnosis of onychomycosis relies on clinical features, traditional KOH direct microscopy and fungal culture. In recent years, dermoscopy has been widely used in the diagnosis and treatment of infectious diseases and has provided new options for the diagnosis of onychomycosis.

Objective

To evaluate the value of dermoscopy in the clinical diagnosis of onychomycosis and to explore the relationship between each clinical subtype and the dermoscopic pattern.

Methods

A retrospective study of 114 cases of clinically suspected onychomycosis was conducted to compare the differences between dermoscopy and fungal pathogenic examination (microscopy and culture) in the diagnostic sensitivity of onychomycosis and to analyze the relationship between nine common dermoscopic modalities and clinical subtypes of onychomycosis.

Results

Among the 114 proposed patients, 87 nails with positive fluorescent staining microscopy and/or positive fungal cultures were diagnosed as onychomycosis. The sensitivity and specificity of dermatoscopy, using the mycological findings as a reference, were 86.21 and 33.33%, respectively. The incidence of common dermatoscopic patterns in the 87 nails with confirmed onychomycosis was as follows: white flocculation in 76 cases (87.35%), longitudinal nail pattern in 72 cases (82.76%), jagged changes in the distal nail plate in 69 cases (79.31%) and yellow staining in 46 cases (52.87%), these four patterns were more commonly seen in the distal lateral subungual onychomycosis and total dystrophic onychomycosis, but there was no statistical difference in the positive dermatoscopic pattern between these two types (P > 0.05).

Conclusion

Dermoscopy can be an important aid in the diagnosis of onychomycosis, especially when fungal microscopy or culture is not appropriate, but this method is still not a substitute for fungal microscopy and culture.

Dermoscopy of skin infestations and infections (entomodermoscopy) - Part II: viral, fungal and other infections

In addition to the infestations and bacterial infections reported in part I, the study of entomodermoscopy also involves descriptions of dermoscopic findings of a growing number of viral and fungal infections, among others. In this article, the main clinical situations in viral infections where dermoscopy can be useful will be described, that is in the evaluation of viral warts, molluscum contagiosum, and even in recent scenarios such as the COVID-19 pandemic. As for fungal infections, dermoscopy is particularly important, not only in the evaluation of the skin surface, but also of skin annexes, such as hairs and nails. The differential diagnosis with skin tumors, especially melanomas, can be facilitated by dermoscopy, especially in the evaluation of cases of verruca plantaris, onychomycosis and tinea nigra.

Nondermatophyte mould onychomycosis

Nondermatophyte moulds (NDMs) onychomycosis is often difficult to diagnose as NDMs have been considered contaminants of nails. There are several diagnostic methods used to identify NDMs, however, repeated laboratory isolation is recommended to validate pathogenicity. With NDM and mixed infection (dermatophytes plus NDM) onychomycosis on the rise, accurate clinical diagnosis along with mycological tests is recommended. Systemic antifungal agents such as itraconazole and terbinafine (e.g. pulse regimen: 1 pulse = every day for one week, followed by no treatment for three weeks) have shown efficacy in treating onychomycosis caused by various NDMs such as Aspergillus spp., Fusarium spp., Scopulariopsis brevicaulis, and Onychocola canadensis. Studies investigating topical therapy and devices for NDM onychomycosis are limited. The emergence of antifungal resistance necessitates the incorporation of antifungal susceptibility testing into diagnosis when possible, for the management of recalcitrant infections. Case studies documented in the literature show newer azoles such as posaconazole and voriconazole as sometimes effective in treating resistant NDM onychomycosis. Treatment with broad-spectrum antifungal agents (e.g. itraconazole and efinaconazole) and other combination therapy (oral + oral and/or oral + topical) may be considerations in the management of NDM onychomycosis.

The change of causative pathogens in toenail onychomycosis

BACKGROUND

Toenail dystrophies are among the most common diseases in adulthood. Onychomycosis is one of the most frequently observed infectious diseases of the nail.

AIM

The aim of this study was to determine the prevalence of fungal agents in the etiology of nail dystrophies such as discoloration, thickening, subungual hyperkeratosis, and onycholysis in toenails and to emphasize the importance of diagnosis by other laboratory confirmation tests since various nail diseases may mimic onychomycosis.

SUBJECTS AND METHODS

Nail samples taken from 53 patients who were admitted to the dermatology clinic with the complaint of toenail disorders were examined by using potassium hydroxide mount, fungal culture, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry methods. Each nail was photographed, and descriptive analysis of the data was performed.

RESULTS

Of 53 patients included in the study, 39 were female (73.6%) and 14 were male (26.4%). The ages of the patients ranged from 14 to 70 years, and the mean age was 37.8 years. No fungi could be isolated in 17 (32%) patients with nail dystrophy, while fungal pathogens were observed in 36 (68%) patients on potassium hydroxide mount, culture, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry examinations. Among nondermatophyte molds, Aspergillus species (52.7%) were identified as the most common fungal pathogen causing onychomycosis.

CONCLUSION

Although fungal pathogenic agents are mostly detected among the diseases causing color changes and deformities in the nails, it should be kept in mind that nail findings of systemic or other skin diseases may mimic onychomycosis and the diagnosis should be confirmed by laboratory tests in addition to clinical manifestations for accurate treatment.

STUDY LIMITATIONS

Other systemic diseases causing nail dystrophy were not questioned in the study.