S1 Guideline onychomycosis.

Onychomycosis is a fungal infection of the fingernails and toenails. In Europe, tinea unguium is mainly caused by dermatophytes. The diagnostic workup comprises microscopic examination, culture and/or molecular testing (nail scrapings). Local treatment with antifungal nail polish is recommended for mild or moderate nail infections. In case of moderate to severe onychomycosis, oral treatment is recommended (in the absence of contraindications). Treatment should consist of topical and systemic agents. The aim of this update of the German S1 guideline is to simplify the selection and implementation of appropriate diagnostics and treatment. The guideline was based on current international guidelines and the results of a literature review conducted by the experts of the guideline committee. This multidisciplinary committee consisted of representatives from the German Society of Dermatology (DDG), the German-Speaking Mycological Society (DMykG), the Association of German Dermatologists (BVDD), the German Society for Hygiene and Microbiology (DGHM), the German Society of Pediatric and Adolescent Medicine (DGKJ), the Working Group for Pediatric Dermatology (APD) and the German Society for Pediatric Infectious Diseases (DGPI). The Division of Evidence-based Medicine (dEBM) provided methodological assistance. The guideline was approved by the participating medical societies following a comprehensive internal and external review.

Fractional CO2 laser ablation leads to enhanced permeation of a fluorescent dye in healthy and mycotic nails-An imaging investigation of laser-tissue effects and their impact on ungual drug delivery.

PURPOSE: Conventional oral antifungal therapies for onychomycosis (OM) often do not achieve complete cure and may be associated with adverse effects, medical interactions, and compliance issues restricting their use in a large group of patients. Topical treatment can bypass the systemic side effects but is limited by the physical barrier of the nail plate. Ablative fractional laser (AFL) treatment can be used to improve the penetration of topical drugs into the nail. This study visualized the effects of laser ablation of nail tissue and assessed their impact on the biodistribution of a fluorescent dye in healthy and fungal nail tissue. METHODS: For the qualitative assessment of CO2 AFL effects on healthy nail tissue, scanning electron microscopy (SEM), coherent anti-Stokes Raman scattering microscopy (CARS-M), and widefield fluorescence microscopy (WFM) were used. To quantitate the effect of laser-pretreatment on the delivery of a fluorescent dye, ATTO-647N, into healthy and fungal nail tissue, ablation depth, nail plate thickness, and ATTO-647N fluorescence intensity in three nail plate layers were measured using WFM. A total of 30 nail clippings (healthy n = 18, fungal n = 12) were collected. An aqueous ATTO-647N solution was directly applied to the dorsal surface of 24 nail samples (healthy n = 12, fungal n = 12) and incubated for 4 hours, of which half (healthy n = 6, fungal n = 6) had been pretreated with AFL (30 mJ/mb, 15% density, 300 Hz, pulse duration <1 ms). RESULTS: Imaging revealed a three-layered nail structure, an AFL-induced porous ablation crater, and changes in autofluorescence. While intact fungal samples showed a 106% higher ATTO-647N signal intensity than healthy controls, microporation led to a significantly increased fluorophore permeation in all samples (p < 0.0001). AFL processing of nail tissue enhanced topical delivery of ATTO-647N in all layers, (average increase: healthy +108%, fungal +33%), most pronounced in the top nail layer (healthy +122%, fungal +68%). While proportionally deeper ablation craters correlated moderately with higher fluorescence intensities in healthy nail tissue, fungal samples showed no significant relationship. CONCLUSION: Fractional CO2 laser microporation is a simple way of enhancing the passive delivery of topically applied ATTO-647N. Although the impaired nail plate barrier in OM leads to greater diffusion of the aqueous solution, AFL can increase the permeability of both structurally deficient and intact nails.

Effect of onychomycosis and treatment on patient-reported quality-of-life outcomes: A systematic review.

BACKGROUND: Onychomycosis is the most common nail disorder, often causing physical, emotional, and aesthetic consequences. The effect of both the condition itself and treatment on quality of life has not been well studied. OBJECTIVE: The objectives of this study were to systematically review the available literature describing the effect of onychomycosis and treatment on quality of life. METHODS: We performed a search of the onychomycosis literature published before April 13, 2020. Articles were included in the review if primary data were presented, patient-reported outcome measures were used, and onychomycosis was specifically examined. RESULTS: Thirty studies were included in the final analysis. Poorest quality-of-life scores were associated with women and fingernail involvement. Quality-of-life scores improved from baseline with all treatment types; there were greater improvements reported with oral treatments compared with topical ones. CONCLUSIONS: This review affirms that onychomycosis significantly influences quality of life, warranting effective treatment. All treatments resulted in quality-of-life improvements; however, studies on oral and topical therapies were of higher quality than those evaluating devices. Increased efforts are needed to understand the effect of the disease and therapy as assessed by validated, nail-specific outcome measures that accurately assess patients' cosmetic, physical, and social difficulties.

Ultrasound-Enhanced Drug Delivery for Treatment of Onychomycosis.

OBJECTIVES: The aim of our study was to determine the effectiveness of using ultrasound (US) to increase the permeability of the nail, with the goal of improving outcomes in the treatment of onychomycosis. METHODS: Porcine nails were used because of their similarity to human nails. A hydrophilic blue dye was used as a drug-mimicking compound. Two sets of experiments were performed: luminosity experiments to assess the dye levels inside the nail after US and sham treatments and diffusion cell experiments for determination of changes in nail permeability due to US application. In both sets of experiments, planar US transducers were used to sonicate the nails at frequencies of 400, 600, and 800 kHz and 1 MHz, an intensity of 1 W/cm2 , and a duration of 5 min in a continuous mode. Modeling studies were also performed to assess the safety of US application to the human toe for later clinical studies. RESULTS: In the luminosity experiments, application of US at frequencies of 600 and 800 kHz led to statistically significant results (P < .05), with an increase in dye delivery into the nail of up to 95% compared to control values. The diffusion cell results found statistical significance (P < .05) at all applied frequencies, with up to a 70% increase in the nail permeability compared to the control. Safety modeling studies found a maximal temperature increase of 4.4 °C in the bone. CONCLUSIONS: Our proposed US method may offer an alternative for improved treatment of onychomycosis. The current maximal temperature increase was found to be at the safety limit, and so pulsing and other alternatives will be investigated to minimize this temperature increase.

Clinico-mycological study of onychomycosis and in vitro antifungal susceptibility of Trichophyton rubrum.

Onychomycosis, a fungal nail infection, is primarily caused by dermatophytes, yeasts, and non-dermatophyte moulds (NDMs). The incidence of this disease and the predominance of specific pathogens vary across different regions and evolve. This study aimed to elucidate the epidemiology of onychomycosis and the pattern of causative pathogens in Beijing, and to ascertain the in vitro antifungal susceptibility profiles of Trichophyton rubrum against itraconazole (ITR), terbinafine (TER), and fluconazole (FLU). Involving 245 patients of onychomycosis with positive fungal culture results, the study implemented internal transcribed spacer (ITS) sequencing of ribosomal DNA (rDNA) on all collected samples. The mean age of the participants was 37.93 ± 13.73 years, with a male-to-female ratio of 1.53:1. The prevalence of toenail infections was significantly higher than that of fingernails. Distal and lateral subungual onychomycosis (DLSO) were the most frequent clinical classifications. PCR results indicated that dermatophytes were the most prevalent pathogens, followed by yeasts and NDMs, among which T. rubrum was the most dominant dermatophyte. TER demonstrated high sensitivity to T. rubrum. However, in clinical settings, some patients with onychomycosis exhibit a poor response to TER treatment. The relationship between in vitro antifungal sensitivity and clinical effectiveness is complex, and understanding the link between in vitro MIC values and clinical efficacy requires further investigation.

Validation of the Onychomycosis Severity Index in a Brazilian population.

Onychomycosis is the most frequent nail disorder, but unfortunately, curative treatment is still a challenge, and commonly the infection recurs. A widely disseminated system to accurately assess and classify the severity of this disease, such as the MASI score for melasma or PASI for psoriasis, is lacking in the literature. In 2011, Carney et al. established and successfully validated the Onychomycosis Severity Index (OSI), proving it to be a simple and reproducible tool. To validate the Onychomycosis Severity Index in a Brazilian population. Four experienced dermatologists were taught how to use the OSI system, and then evaluated photographs of 24 nails. There was no consultation between the dermatologists, and the results were evaluated by an impartial third party. A statistically significant (p<0.001) high degree of agreement was observed between the evaluators and overall OSI score (mild, moderate or severe) as well as its subcategories (area of involvement, proximity to the nail matrix and presence of dermatophytoma or hyperkeratosis). OSI is a very useful tool to improve the clinical assessment of onychomycosis and support clinical trial inclusion criteria (p<0.001). It also provides important prognostic data and allows for a better follow-up of treatment efficacy.

A phase II, randomized, double-blind, placebo-controlled, parallel group, dose-ranging study to investigate the efficacy and safety of 4 dose regimens of oral albaconazole in patients with distal subungual onychomycosis.

BACKGROUND: Onychomycosis is effectively treated with terbinafine and itraconazole. However, frequent repeated dosing is required, and hepatic and cardiac adverse events may occur. OBJECTIVES: Evaluate efficacy and safety of albaconazole, a novel triazole, for once-weekly treatment of distal subungual onychomycosis of the great toenail. METHODS: This double-blind, phase II study randomized 584 patients to receive albaconazole 100 to 400 mg or placebo weekly for 24 or 36 weeks. Effective treatment was measured as mycologic cure and clear or almost clear nail at week 52. RESULTS: All treatment groups achieved greater effective treatment rates (21%-54%) compared to placebo (1%; P < .001 for all groups) at week 52. Effective treatment was attained at week 24 in ≥5% of patients in most groups. Most adverse events were mild or moderate, and treatment-related adverse events were all ≤3%. No treatment-related hepatic or cardiac serious adverse events were observed. LIMITATIONS: The follow-up period was likely too short to detect maximal efficacy; cure rates were increasing at study end. The efficacy and tolerability of albaconazole were not compared with other available treatments, and the global change in target toenail scale was subjective. CONCLUSIONS: Albaconazole was well tolerated at all doses and resulted in high cure rates for onychomycosis.

Truth or Trend - Misinformation Spreading Fast on TikTok: A Cross-Sectional Analysis of Onychomycosis Content.

Background: Onychomycosis is the most frequently diagnosed nail condition in clinical practice. With the growing popularity of TikTok and online health information-seeking behavior, it is imperative to understand onychomycosis-related content on this platform. Objective: Our objective was to assess content and quality of the most popular onychomycosis-related content on TikTok. Methods: We queried TikTok for videos using the search terms "onychomycosis" and "nail fungus" for the top 100 videos by view count, with DISCERN scoring used to rate videos for quality. Results: Average DISCERN score was 1.77 and dermatologists posted videos with the highest mean score (2.56). Most of the videos were educational (72%) and/or related to treatment (69%). Home remedies were recommended more often (58%) than FDA-approved therapies (7%). Physician versus nonphysician posted videos had higher mean DISCERN score (2.28 vs. 1.44) (p < 0.001), greater view number (1,209,953 vs. 343,993) (p < 0.05), and more often discussed medical therapy (p < 0.05). Conclusion: While social media is a valuable resource for providing medical information to an interminable audience, there are significant shortcomings. Therefore, we recommend that dermatologists advise patients against relying on social media for medical information and consider using social media to provide accessible evidence-based health education on onychomycosis.

A Bibliometric Analysis of the Top 100 Highly Cited Onychomycosis Publications Using SCOPUS Database (1972-2022).

Introduction: Onychomycosis represents half of nail disorders seen in clinical practice. Despite its high prevalence, a bibliometric analysis has not been performed. We aimed to identify the top 100 highly cited onychomycosis publications over the last 50 years to better understand research trends. Methods: SCOPUS was searched for onychomycosis publications, using "onychomycosis" and "nail fungus" 1/1/1972-12/31/22 on 3/25/23. Top 100 highly cited publications were recorded and ranked by total citation count. Results: Total citation count was 13,456, with the top 10 articles with highest citation count/year having average 28.7 citations/year. Most articles were published in high IF journals. From 1982 to 2011 (no treatment articles - 1972-1981), there was an 8.6% increase in articles discussing treatment. Overall, 42% of first authors were female. Conclusion: We found an overall increase in articles discussing onychomycosis therapies over time, with the majority published in high IF journals. We also found a relatively greater percentage of female first authors compared to studies on other dermatologic topics. While total citation count remains a widely used metric of impact in bibliometric studies, average citation count/year may be a better measure of impact and should be considered in future studies.

Two Novel Human Leukocyte Antigen Alleles Are Associated with Decreased Risk of Onychomycosis in a Large Cohort of Danish Blood Donors.

Introduction: Antigen presentation and antimicrobial immune responses involve the human leukocyte antigen (HLA) system. Onychomycosis is primarily caused by dermatophytes and affects around 5.5% of the population worldwide. Yet, only limited data exist on the associations between the HLA system and onychomycosis. Thus, the objective of the study was to investigate if there is an association between HLA alleles and onychomycosis. Methods: Participants in the Danish Blood Donor Study were defined as cases of onychomycosis and controls based on antifungal prescriptions in the national prescription registry. Associations were investigated using logistic regressions adjusted for confounders and were Bonferroni corrected for multiple tests. Results: A total of 3,665 participants were considered onychomycosis cases, and 24,144 participants were considered controls. We found two protective HLA alleles of onychomycosis: DQB1*06:04, odds ratios (OR) 0.80 (95% confidence interval (CI) 0.71-0.90), and DRB1*13:02, OR 0.79 (95% CI: 0.71-0.89). Conclusion: The finding of two novel protective alleles of onychomycosis indicates that certain HLA alleles have certain antigen presentation properties affecting the risk of fungal infection. These findings may provide the basis for future research identifying immunologically relevant antigens of fungi causing onychomycosis, which could ultimately lead to targets of new drugs with antifungal effects.

Nail Clipping with PAS Stain and Correlation with Fungi Isolated in Culture: A Valuable Exchange in the Diagnosis of Onychomycosis.

Introduction: The etiological agents of onychomycosis are dermatophyte fungi, nondermatophyte filamentous fungi (NDFF), and yeasts. Nail clippings are an accurate tool for diagnosing onychomycosis. The objective of this study was to correlate the characteristics of fungi observed in nail clipping examinations with the results for agents isolated in culture, indicating whether the fungus found on microscopy is a dermatophyte, NDFF, or yeast. Methods: An observational descriptive study of onychomycosis nail clippings stained with PAS comparing culture results with microscopic criteria of fungi morphology, arrangement/orientation, and location of organisms in the nail and presence of neutrophils, serous lakes, and bacterial colonies was conducted. Results: Thirty-three nail clippings from 29 participants were analyzed. A statistically significant correlation (p < 0.05) was found between smooth/thin/long hyphae with a "combed" pattern and dermatophyte agents (sensitivity 89.4%, specificity 91.5%), and between irregular/thick/short anarchic distributed hyphae and nondermatophytes (sensitivity 61.5%, specificity 89.4%). No statistical association with region where fungi were in the nail or with the presence of neutrophils, serous lakes or bacteria was found. Small, rounded, yeast-like organisms correlated with Candida infection. Conclusions: Although not a substitute for culture, microscopic analysis of fungal structures offers good accuracy for differentiating agents of onychomycosis.

Nail Changes in People Living with Human Immunodeficiency Virus: Observational and Cross-Sectional Study in a Third-Level Hospital.

Introduction: Nail changes in people living with human immunodeficiency virus (HIV) have been scarcely reported. The aim of this study was to establish the frequency and characteristics of nail alterations observed in adults with HIV infection in a third-level hospital in Mexico. Method: Observational and cross-sectional study carried out in 205 patients receiving care at the HIV/AIDS Clinic of the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán (INCMNSZ) in Mexico City. We performed a nail and iconographic assessment of both hands and toenails. We collected information of demographic and clinical variables, as well as drugs use, and antiretroviral treatment used by the participants through a questionnaire and from medical records. We performed direct cytological examinations and nail mycological cultures in participants with symptoms of onychomycosis. Results: The participants were predominantly male patients (91.2%), with a mean age of 41 (range 21-78) years, under antiretroviral therapy (91.2%), with a suppressed viral load (78.5%) and mean CD4+ lymphocyte count of 379.5 (range 20-1,162) cells/µL. Fitzpatrick's IV phototype was prevailing in the studied population (70%). Nail changes were documented in 72.2% of the patients; being pigmentary changes (37.1%) and trauma (30.7%) the most frequent. Onychomycosis was observed in 26.3%; with total dystrophic onychomycosis as the most frequent clinical variant (68.5%). We obtained fungal isolates in 59.3% of participants and Candida parapsilosis was the most frequent of these (37.5%). Conclusions: We observed a high prevalence of nail changes with very diverse etiology, as well as a variety of nondermatophytic yeasts and molds isolates associated with cases with onychomycosis. These findings reinforce and confirm the need for routine nail examination and stress the importance of medical personnel working with people living with HIV to have broad knowledge of nail pathology.

An Increase in Specialist Treatment for Onychomycosis: An Unexplained Tendency. A Retrospective Study of Patients Treated for Onychomycosis in Danish Hospitals from 1994 to 2018.

Onychomycosis is a common disease with a significant negative impact on quality of life. While the disease is usually manageable in general practice, a proportion of patients need specialist treatment in academic hospital clinics. However, it is an unknown question whether the incidence in those needing specialist treatments is changing. Furthermore, the comorbidity burden in this patient population severely affected by onychomycosis has never been characterized. We conducted a retrospective study on patients treated for onychomycosis in Danish hospitals from 1994 to 2018. The cohort was observed for 24 years, and the data comprise 7.2 million Danes and their hospital diagnoses. A disease trajectory algorithm was used to examine the comorbidity burden in the cohort. A total of 2,271 patients received hospital treatment for onychomycosis during the time period, of which 1358 (59.8%) were men. The data show an increase in the incidence of hospital-treated cases since 2012 and that the most common comorbidities in this patient population include cardiovascular disease, alcohol-related diagnoses, and diabetes. One explanation of the increase in specialist treatment may include a general increase in patients with decreased resilience to fungal disease. This lack of resilience may both include an increasing elderly population with atherosclerosis, diabetes, and immunosuppression but also a potential increase in patients treated with immunosuppressive agents. Another possible explanation may include a shift in patient expectations in the case of treatment failure. Thus, patients may have an increasing demand for specialist treatment. While our data document an increase in the number of patients in need of specialist treatment for onychomycosis, we suggest future research to examine the general incidence of onychomycosis but also whether this increase in an apparently recalcitrant disease may be attributed to increased antifungal resistance, more specialist treatment options, or increased attention to dermatomycoses.

Onychomycosis on YouTube: A Cross-Sectional Analysis.

Background: While the Internet remains a popular source of health information, YouTube may contain bias and incomplete information regarding common dermatological conditions. Objective: Our objective was to quantify onychomycosis treatment recommendations on YouTube. Methods: We searched YouTube for "nail fungus," "toenail fungus," "onychomycosis treatment," "onychomycosis," and "nail fungus treatment" in separate searches. The top 30 videos meeting inclusion criteria in each search were viewed for video demographics and treatment recommendations. Results: Analysis was performed on 102 videos. The majority of videos (81.3%) were intended for patient education. Analyzing videos by speaker, 50.0% featured a podiatrist, 13.7% a nondermatologist physician or other medical professional, 10.8% a patient or blogger, 6.9% a dermatologist, and 2.0% a nail technician. Videos recommended FDA-approved therapies, as well as OTC products. The most recommended medical therapies included oral terbinafine and laser therapy, mentioned in 29 and 28 videos, respectively. Various natural remedies were recommended, with tea tree oil being endorsed in 23 videos. Conclusion: YouTube offers patient education on a range of treatment options for onychomycosis. We caution patients against starting treatments based on social media recommendations and encourage dermatologists to utilize social media to educate the public on common dermatological conditions.

Fungal Viability of Nail Dust from Onychomycosis Abrasion: A Pilot Study.

INTRODUCTION: Onychomycosis is a frequent complaint in dermatological practice and corresponds to the most common nail disease. The treatment of onychomycosis remains a challenge, as several factors end up compromising and making treatment difficult. Nail abrasion is considered a useful method in many cases. However, there is controversy about this approach, as there is an aerosol formation that could contaminate the environment and cause fungal changes or hypersensitivity reactions by the disseminated dust. We conducted a pilot study to investigate the fungal viability of nail particles from nails with onychomycosis after abrasion procedure. METHODS: In this study, nail dust from the gloves and mask, used in the procedure, was collected from 9 patients with clinical and dermoscopic diagnoses of onychomycosis. RESULTS: Hyaline septate hyphae were found in 12 materials (gloves and/or masks) from 7 patients. However, these hyphae were morphologically deformed or mutilated in all exams. In Mycosel® agar, there was no growth of any fungus. DISCUSSION/CONCLUSION: The absence of dermatophyte isolation in all fungal cultures may demonstrate that the deformed fungal structures shown are not viable and would not present risks of contamination after nail abrasion.

First Subungual Cryptococcosis Described in an HIV Patient with Disseminated Cryptococcosis.

BACKGROUND: Cutaneous cryptococcosis occurs in 10-15% of patients with disseminated cryptococcosis. It typically presents as papulonodular molluscum-like lesions, but it can also produce a wide variety of lesions. Cryptococcal infection of the nail unit has never been reported. CASE REPORT: A 28-year-old woman with a history of HIV with disseminated cryptococcosis in complete remission was referred to evaluate a subungual swelling of the right middle finger. Examination revealed an ulcero-burgeoning nodule over the right middle finger's subungual area with onycholysis, eschar, and erosion. An excisional biopsy was performed. Histopathological analysis demonstrated multiple histiocytic granulomas centered by encapsulated yeast cells. Culture grew Cryptococcus neoformans var. neoformans. After 9 months of follow-up, there was no recurrence of the lesion. DISCUSSION: It is the first reported case of nail involvement in the course of cutaneous cryptococcosis. Definitive diagnosis required pathology and culture. Cryptococcal infection of the nail unit was recalcitrant to systemic therapy while the remaining infection cleared. Our case report suggests that surgical excision associated with systemic therapy is the best treatment approach for subungual cryptococcosis. Recognition of rare manifestations of cutaneous cryptococcosis, such as ours, is essential because HIV cases increase continuously.

Safety of current therapies for onychomycosis.

INTRODUCTION: Onychomycosis is the most common nail disease seen in clinical practice. Treatment options include systemic and topical therapies, as well as devices. Following clinical and mycologic diagnosis, treatment must be individualized, accounting for disease severity, infecting organism(s), comorbidities, patient characteristics and drug/device efficacy. Safety is the most important consideration in choosing the most appropriate therapeutic modality. AREAS COVERED: This review covers currently available treatments for onychomycosis, with an emphasis on safety and tolerability. Medications and devices were analyzed for side effects, drug-drug interactions, and safety during pregnancy and breastfeeding. EXPERT OPINION: Systemic antifungals offer greater efficacy for onychomycosis treatment but are limited by risks of systemic toxicity and drug-drug interactions. The risk of terbinafine-induced hepatotoxicity is negligible in healthy patients. Systemic therapies, especially azole antifungals, are associated with numerous drug-drug interactions, some of which are life-threatening and fatal. Thus, a detailed medication history is critical before prescribing these medications. Topical antifungals are well tolerated and generally safe, with only potential local side effects. Systemic and topical onychomycosis treatments should not be prescribed during pregnancy and breastfeeding. Laser therapy is likely less effective than systemic and topical therapies, but may be safely used during pregnancy and breastfeeding.

Impact of Onychomycosis on the Quality of Life: Dermatology Life Quality Index-Based Cross-Sectional Study.

BACKGROUND: Onychomycosis (OM) is a common fungal infection of the nail unit with a worldwide prevalence of 5%. Though apparently a benign and innocuous entity, it carries significant psychosocial morbidity. The Dermatology Life Quality Index (DLQI) is based on a simple practical questionnaire that considers multiple psychological and social domains. Its utility in OM by far remains unexplored. OBJECTIVE: To determine the DLQI in patients suffering from OM. METHODS: The DLQI questionnaire was answered by 100 patients with an established diagnosis of OM. RESULTS: The mean DLQI of our study subjects was 6.1 ± 3.3. Most patients (46%) belonged to the DLQI 2 group (moderate effect). Among these, most patients reported disease duration of 1-5 years (50%). Among patients responding to DLQI 3 (very large effect), a higher significant proportion were females (66.7%). The most inconvenient domain was seeking treatment for OM and social embarrassment due to the disease. CONCLUSION: As DLQI is an easy scoring method, it can be used for assessing quality of health in OM. OM causes moderate effect on quality of life (mostly DLQI 2), thereby making its treatment mandatory.

Successful Treatment of Dermatophytomas in 19 Patients Using Efinaconazole 10% Solution.

Dermatophytomas represent a historically difficult-to-treat complication of onychomycosis and are characterized by adherent fungal masses encased in biofilm in the subungual space. In this study, we evaluated the efficacy of 10% efinaconazole solution in patients with onychomycosis complicated by dermatophytomas. Cure was achieved in 65% of target great toenails. All dermatophytomas resolved and did not recur during the study. The median time to dermatophytoma resolution was 16 weeks.