Dermatophytomas in Onychomycosis: A Scoping Review of Prevalence, Diagnosis, and Treatment.

BACKGROUND: Dermatophytoma, also described as a longitudinal streak/spike, is a form of onychomycosis that presents as yellow/white streaks or patches in the subungual space, with dense fungal masses encased in biofilm. This scoping review of the literature was conducted to address a general lack of information about the epidemiology, pathophysiology, and treatment of dermatophytomas in onychomycosis. METHODS: A search was performed in the PubMed and Embase databases for the terms "longitudinal spike" or "dermatophytoma." Outcomes of interest were definition, prevalence, methods used for diagnosis, treatments, and treatment efficacy. Inclusion and exclusion of search results required agreement between two independent reviewers. RESULTS: Of a total of 51 records, 37 were included. Two reports provided the first unique definitions/clinical features of dermatophytomas. Overall, many descriptions were found, but one conclusive definition was lacking. Prevalence data were limited and inconsistent. The most frequently mentioned diagnostic techniques were clinical assessment, potassium hydroxide/microscopy, and fungal culture/mycology. Oral terbinafine and topical efinaconazole 10% were the most frequently mentioned treatments, followed by topical luliconazole 5% and other oral treatments (itraconazole, fluconazole, fosravuconazole). In studies with five or more patients without nail excision, cure rates were highest with efinaconazole 10%, which ranged from 41% to 100% depending on the clinical and/or mycologic assessment evaluated. Other drugs with greater than or equal to 50% cure rates were topical luliconazole 5% (50%), oral fosravuconazole (57%), and oral terbinafine (67%). In studies that combined oral terbinafine treatment with nail excision using surgical or chemical (40% urea) methods, cure rates ranged from 50% to 100%. CONCLUSIONS: There is little published information regarding dermatophytomas in onychomycosis. More clinical research and physician education are needed. Although dermatophytomas have historically been considered difficult to treat, the efficacy data gathered in this scoping review have demonstrated that newer topical treatments are effective, as are oral antifungals in combination with chemical or surgical methods.

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.

Number of Affected Nails Is the Primary Determinant of Efinaconazole 10% Solution Usage for Onychomycosis.

Good adherence to treatment is necessary for the successful treatment of onychomycosis and requires that an appropriate amount of medication be prescribed. Most prescriptions for efinaconazole 10% solution, a topical azole antifungal, are for 4 mL per month but there are no data on patient factors or disease characteristics that impact how much medication is needed. Data from two phase 3 studies of efinaconazole 10% solution for the treatment of toenail onychomycosis were pooled and analyzed to determine monthly medication usage based on the number of affected toenails, percent involvement of the target toenail, body mass index (BMI), and sex. Participants with two or more affected nails required, on average, >4 mL of efinaconazole per month, with increasing amounts needed based on the number of nails with onychomycosis (mean: 4.39 mL for 2 nails; 6.36 mL for 6 nails). In contrast, usage was not greatly impacted by target toenail involvement, BMI, or sex. Together, these data indicate that the number of affected nails should be the major consideration when determining the monthly efinaconazole quantity to prescribe. J Drugs Dermatol. 2024;23(2):110-112.    doi:10.36849/JDD.7676.

Line-field confocal optical coherence tomography, a novel non-invasive tool for the diagnosis of onychomycosis.

BACKGROUND AND OBJECTIVES: Onychomycosis is common and important to distinguish from other nail diseases. Rapid and accurate diagnosis is necessary for optimal patient treatment and outcome. Non-invasive diagnostic tools have increasing potential for nail diseases including onychomycosis. This study evaluated line-field confocal optical coherence tomography (LC-OCT) as a rapid non-invasive tool for diagnosing onychomycosis as compared to confocal laser scanning microscopy (CLSM), optical coherence tomography (OCT), and conventional methods. PATIENTS AND METHODS: In this prospective study 86 patients with clinically suspected onychomycosis and 14 controls were examined using LC-OCT, OCT, and CLSM. KOH-preparation, fungal culture, PCR, and histopathology were used as comparative conventional methods. RESULTS: LC-OCT had the highest sensitivity and negative predictive value of all methods used, closely followed by PCR and OCT. Specificity and positive predictive value of LC-OCT were as high as with CLSM, while OCT scored much lower. The gold standard technique, fungal culture, showed the lowest sensitivity and negative predictive value. Only PCR and culture allowed species differentiation. CONCLUSIONS: LC-OCT enables quick and non-invasive detection of onychomycosis, with advantages over CLSM and OCT, and similar diagnostic accuracy to PCR but lacking species differentiation. For accurate nail examination, LC-OCT requires well-trained and experienced operators.

Inter-observer reliability of the Onychomycosis Severity Index depending on clinical experience: A review of 50 cases.

BACKGROUND: Onychomycosis (ONM) is the most prevalent nail unit pathology, and its severity and monitoring are often based on the visual judgement of clinicians. OBJECTIVE: The objective of this study is to assess the reliability of the Onychomycosis Severity Index (OSI) classification when utilized by three clinicians with varying levels of clinical experience: an experienced podiatrist (with 5 years of experience), a moderately experienced podiatrist (with 2 years of experience) and an inexperienced podiatrist (a recent graduate familiar with the OSI classification but lacking clinical experience). Additionally, we compared the severity assessments made through visual inspection with those determined using the OSI by different clinicians. METHODS: We evaluated reliability using the intraclass correlation index (ICC), analysing 50 images of ONM. RESULTS: The OSI demonstrated a very high level of reliability (ICC: 0.889) across clinicians, irrespective of their experience levels. Conversely, a statistically significant increase in severity was observed when comparing visual assessments with the OSI (p < .001) for ONM severity evaluation. CONCLUSION: The OSI proves to be a reproducible classification system, regardless of the clinical experience of the practitioner employing it.

[Conventional and molecular diagnostics in onychomycosis-part 2 : Molecular identification of causative dermatophytes by polymerase chain reaction and sequence analysis of the internal transcribed spacer region of ribosomal DNA]. / Konventionelle und molekulare Diagnostik bei Onychomykose ­ Teil 2 : Molekulare Identifizierung der ursächlichen Dermatophyten mit Polymerasekettenreaktion und Sequenzanalyse der ITS("internal transcribed spacer")-Region der ribosomalen Desoxyribonukleinsäure.

Dermatophyte identification using traditional methods such as optics-based direct fluorescence microscopy and culture is nowadays supplemented by molecular biological methods. The validity of dermatophyte DNA detection with direct uniplex-polymerase chain reaction-enzyme immunoassay (PCR-EIA) in nail samples was proven by sequence analysis of the ribosomal internal transcribed spacer (ITS) region. A total of 108 dermatophytes, isolated from patients with onychomycosis, were positive for Trichophyton rubrum (TR) and Trichophyton interdigitale (TI) in culture and/or uniplex-PCR-EIA. Conventional methods for dermatophyte identification were complemented by direct uniplex-PCR-EIA and sequence analysis of the ribosomal ITS region (18S rRNA, ITS1, 5.8S rRNA, ITS2, 28S rRNA). Of 108 patients (average age 62, median age 73), 56 showed cultural growth with 31 of them being identified as TR and 23 as TI. There was high agreement with the sequence analysis. Surprisingly, the pathogen of a single nail sample was identified as T. quinckeanum (formerly T. mentagrophytes sensu stricto), a rare zoophilic dermatophyte in Germany. A single TI strain turned out to be a misidentified T. tonsurans based on the sequence analysis. In all, 34 of the 52 specimens lacking cultural growth were detected by PCR as TR, and 18 specimens could be identified as TI. The results of dermatophyte identification of culture-negative nail samples were also in agreement with the results of sequence analysis. Molecular biological methods are well applicable, and they show high reliability for direct dermatophyte identification in nail samples without prior cultivation. Especially for nail samples without cultural growth, PCR-based dermatophyte identification was highly specific and sensitive.

A comprehensive review of nondermatophyte mould onychomycosis: Epidemiology, diagnosis and management.

Nondermatophyte moulds (NDMs) are widely distributed and can be detected in association with mycotic nails; however, sometimes it can be challenging to establish the role of NDMs in the pathogenesis of onychomycosis (i.e. causative vs. contaminant). In studies where the ongoing invasive presence of NDMs is confirmed through repeat cultures, the global prevalence of NDMs in onychomycosis patients is estimated at 6.9% with the 3 most common genus being: Aspergillus, Scopulariopsis and Fusarium. NDM onychomycosis can, in many cases, appear clinically indistinguishable from dermatophyte onychomycosis. Clinical features suggestive of NDMs include proximal subungual onychomycosis with paronychia associated with Aspergillus spp., Fusarium spp. and Scopulariopsis brevicaulis, as well as superficial white onychomycosis in a deep and diffused pattern associated with Aspergillus and Fusarium. Longitudinal streaks seen in patients with distal and lateral onychomycosis may serve as an additional indicator. For diagnosis, light microscopic examination should demonstrate fungal filaments consistent with an NDM with at least two independent isolations in the absence of a dermatophyte; the advent of molecular testing combined with histological assessment may serve as an alternative with improved sensitivity and turnover time. In most instances, antifungal susceptibility testing has limited value. Information on effective treatments for NDM onychomycosis is relatively scarce, unlike the situation in the study of dermatophyte onychomycosis. Terbinafine and itraconazole therapy (continuous and pulsed) appear effective to varying extents for treating onychomycosis caused by Aspergillus, Fusarium or Scopulariopsis. There is scant literature on oral treatments for Neoscytalidium.

[Conventional and molecular diagnostics in onychomycosis-part 1 : Conventional differentiation of dermatophytes-Trichophyton rubrum, Trichophyton interdigitale]. / Konventionelle und molekulare Diagnostik bei Onychomykose ­ Teil 1 : Konventionelle Differenzierung von Dermatophyten ­ Trichophyton rubrum, Trichophyton interdigitale.

Onychomycosis is a common infectious nail disease occurring worldwide. The mycological diagnosis of onychomycosis is primarily used for differential diagnostic differentiation from other, mostly inflammatory nail diseases, such as nail psoriasis or onychodystrophies of other causes. Conventional laboratory diagnostics when onychomycosis is suspected is based on microscopic detection of fungi in the nail material using fluorescence-optical potassium hydroxide preparations and culture of the pathogen. Molecular amplification methods allow a more sensitive and specific identification of the causative dermatophyte. Here, in 108 patients with onychomycosis, the dermatophytes were identified by culture and/or molecular biology using polymerase chain reaction (PCR) and the species identification was confirmed with subsequent sequencing. The dermatophytes were analyzed based on macromorphological and microscopic features. A dermatophyte was cultured in 56 of the 108 patients. Among them were 31 isolates of Trichophyton (T.) rubrum and 25 of T. interdigitale. All species identifications were subsequently confirmed by rDNA sequencing with concordant results in 54 of 56 patients. Two primarily as T. interdigitale identified specimens were revealed to be T. quinckeanum and T. tonsurans by molecular methods. T. quinckeanum, which is a zoophilic dermatophyte and a so-called emerging pathogen in dermatomycology, was isolated here for the first time as the causative agent of onychomycosis. The other dermatophyte, initially thought to be T. interdigitale, turned out to be T. tonsurans on molecular biology. This anthropophilic dermatophyte is also a rarity in onychomycosis. In addition, T. rubrum was identified by PCR in 34 of the 52 nail specimens that did not grow culture, and T. interdigitale in 18 nail specimens. However, the morphological identification of the four different dermatophytes species proved problematic. Neither the colony morphology nor the microscopic features of the dermatophytes allow clear differentiation of the pathogens. Microconidia, macroconidia, chlamydospores, and arthrospores are inconsistent in occurrence, number, microscopic distribution, and shape. The urease activity also did not allow an assignment of the dermatophyte species. These results indicate that the most sensitive detection and reliable identification of causative dermatophytes in onychomycosis is only possible by molecular methods.

Onychoscopic characteristics of Trichophyton rubrum and Trichophyton interdigitalis fungal infections: A multicentric study.

BACKGROUND: Trichophyton rubrum and Trichophyton mentagrophytes variant interdigitalis are the most frequent etiologic agents of onychomycosis. Diagnosis of certainty requires mycological examination, which often results unfeasible. OBJECTIVES: The aim of our study is to describe pathogen specific dermoscopic features, allowing a differential diagnosis without the need for cultural examination, in order to prescribe the most appropriate treatment anyway. PATIENTS AND METHODS: We conducted an observational retrospective study on 54 patients with a culture proven diagnosis of distal subungual onychomycosis of the toenail, caused by Trichophyton rubrum or Trichophyton mentagrophytes variant interdigitalis. Using a videodermatoscope we collected data on nail colour (white, yellow, orange, brown, dark) and on dermoscopic patterns (aurora, spikes, jagged, ruin, linear edge, dots, striae). RESULTS: Fifty-four patients, with a total of 72 nails, were eligible for this study. Analysing the association between discoloration of the nail plate and type of infection (T. rubrum or T. interdigitalis), no correlation turned out to be statistically significant. Instead, significant associations between spikes and T. rubrum infection and striae and infection from T. interdigitalis were identified. Finally, a 100% specificity was identified for white colour and ruin pattern for T. rubrum infection, and brown colour, jagged border and aurora pattern for T. interdigitalis. CONCLUSIONS: Trying to find relationships between specific pathogens and dermoscopic patterns, we found out an association between spikes and striae and T. rubrum and T. interdigitalis respectively. Further larger studies are however necessary to evaluate our preliminary findings.

Onychomycosis due to Fusarium species in different continents, literature review on diagnosis and treatment.

Fusarium species are an emerging cause of onychomycosis, and the number of cases has dramatically increased in recent decades worldwide. This review presents an overview of the onychomycosis cases caused by Fusarium species and diagnosis and treatment that have been reported in the literature. The most common causative agent of onychomycosis is F. solani species complex, which accounts for 11.68% of the cases of Fusarium onychomycosis, followed by the F. oxysporum species complex (164 out of 1669), which is accounted for 9.83% of the total. F. fujikuroi species complex (42 out of 1669) and F. dimerum species complex (7 out of 1669) are responsible for 2.52% and 0.42 cases, respectively. Fusarium nail infections were reported in patients aged range 1-98, accounting for 5.55% (1669 out of 30082) of all cases. Asia has the highest species diversity of Fusarium onychomycosis (31.51%). South America accounts for 21.09%, and the most common causative agent is F. solani (19.32%), followed by F. oxysporum species complex (15.63%). Europe accounts for 4.90% of cases caused by F. oxysporum, followed by F. solani. Africa accounts for 23.87% of the cases due to the F. solani species complex, followed by F. oxysporum and F. fujikuroi. Distal and lateral subungual onychomycosis was the most common clinical symptom accounting for 58.7% (135 out of 230) of the cases. Data analysis relieved that terbinafine and itraconazole are active treatments for Fusarium onychomycosis. For a definitive diagnosis, combining of direct examination, culture and sequencing of the elongation factor of translation 1α are recommended. Accurate identification of the causative agents of onychomycosis due to Fusarium species and antifungal susceptibility testing is essential in patient management.

Novel Discoveries and Clinical Advancements for Treating Onychomycosis: A Mechanistic Insight.

Onychomycosis continues to be the most challenging disease condition for pharmaceutical scientists to develop an effective drug delivery system. Treatment challenges lie in incomplete cure and high relapse rate. Present compilation provides cumulative information on pathophysiology, diagnostic techniques, and conventional treatment strategies to manage onychomycosis. Novel technologies developed for successful delivery of antifungal molecules are also discussed in brief. Multidirectional information offered by this article also unlocks the panoramic view of leading patented technologies and clinical trials. The obtained clinical landscape recommends the use of advanced technology driven approaches, as a promising way-out for treatment of onychomycosis. Collectively, present review warrants the application of novel technologies for the successful management of onychomycosis. This review will assist readers to envision a better understanding about the technologies available for combating onychomycosis. We also trust that these contributions address and certainly will encourage the design and development of nanocarriers-based delivery vehicles for effective management of onychomycosis.

Nail psoriasis in China: A prospective multicentre study.

BACKGROUND: Data on nail psoriasis (PsO) in China are scarce. OBJECTIVES: To provide nail PsO-related data regarding epidemiologic characteristics, manifestations, fungal infections, arthritic complaints and treatments that may facilitate improved patient management globally. METHODS: From August 2021 to August 2022, patients with nail PsO were enrolled in a prospective multicentre observational study at 25 hospitals in China. We collected and analysed data concerning nail PsO demography, clinical signs, fungal detection, arthritic symptoms and treatment. RESULTS: A total of 817 patients with nail PsO were involved, with a mean body mass index of 24.13 ± 2.93. In addition, 71.41% of the patients were male. The Nail PsO Severity Index score was weakly positively correlated with body surface area. The percentage of nail involvement was 95.29% for fingernails and 57.18% for toenails, with pitting (67.11%) and subungual hyperkeratosis (60.40%) being the most prevalent manifestations, respectively. Toenails showed a significantly higher frequency of nailfold scales, subungual hyperkeratosis and nail plate crumbling and a lower frequency of splinter haemorrhages, pitting and erythema of the lunula. A total of 13.26% of the PsO patients had onychomycosis, and 77.08% were observed in the toenails. Articular symptoms were reported by 12.17% of the patients, with the peripheral type being predominant. Significant associations between articular symptoms and nailfold swelling, subungual hyperkeratosis, nailfold scales, onycholysis and longitudinal ridges were found. Only 2.30% (20 out of 871) of patients with nail PsO received treatment. The most frequently employed therapy for cutaneous PsO with nail involvement was biologic therapy (n = 366). CONCLUSIONS: PsO showed distinct manifestations in the toenails and fingernails. Additionally, toenail PsO combined with onychomycosis requires special attention. Articular symptoms in psoriatic patients are associated with specific nail changes. It is important to research and advocate for more potent treatments for nail PsO.

Pathophysiology and Management of Onychomycosis and Novel Approaches for Effective Transdermal Applications.

Onychomycosis is the most common fungal nail infection accounting for 50% of nail disorders. This infection is most common in the toenails than in the nails of the fingers. It is caused by various fungal species like Trichophyton rubrum, Trichophyton mentagrophytes, Scopulariopsis brevicaulis, Aspergillus spp, Fusarium spp, Acremonium spp, Alternaria spp, and Neoscytalidium. Among them, dermatophyte fungus is involved in 70% to 80% of infections. Clinically, there are five types of onychomycosis classified based on causative organism and location of infection origin. Diagnosis of this infection uses a mycological study of nail samples using multiple staining techniques like periodic acid-Schiff, calcofluor, Grocott methenamine silver, fluorescence, and microscopy. The major risk factors of this infection include diabetes mellitus, psoriasis, peripheral vascular diseases, obesity, metabolic syndrome, nail trauma, human immunodeficiency virus and/or acquired immunodeficiency syndrome, immune-compromised individuals, chronic kidney failure, athletic activity, smoking, and hyperlipidemia. The treatment options for onychomycosis include topical and systemic antifungal agents, nanoparticles, laser therapy, photodynamic therapy, and nail avulsion. This article describes several types of onychomycosis, symptoms, diagnosis, currently available therapy and its drawback, current research to rectify the issues, and future medicinal approaches to improve patient health.

A peculiar case of onychomycosis caused by Cladosporium halotolerans.

A 49-year-old patient with changes in the nails of the hallux for 10 years was diagnosed with onychomycosis. The identity of the causative agent was confirmed as Cladosporium halotolerans from the Cladosporium sphaerospermum species complex using molecular techniques. MALDI-TOF identified the agent as C. sphaerospermum complex species. Overall, species such as onychomycosis agents should attract special attention to avoid mistakes in the identification process while considering a probable contaminant as responsible for the disease. These species deserve attention since there are rare descriptions of them as causes of onychomycosis. It is important to recognize them as causes of disease and not just as a probable contaminant.

Comparing the Efficacy for Pulse Versus Continuous Dose Terbinafine Therapy in Patients With Onychomycosis.

Recently, treatment outcomes in patients with toenail onychomycosis have improved considerably due to more effective oral antifungal medications such as terbinafine and itraconazole. These medications can either be used continuously for several weeks at a lower dose or intermittently (pulsed) at a higher dose. Previous literature comparing pulse and continuous therapy has generated mixed results.  Our study aims to compare the efficacy, in terms of clinical cure rate, of continuous vs pulse dose terbinafine regimens for toenail onychomycosis. Sixty patients with onychomycosis of Fitzpatrick skin types IV to VI, between 15 and 65 years of age, were divided into a continuous treatment group receiving 250 mg terbinafine once daily for 12 weeks and a pulse treatment group receiving 250 mg twice daily terbinafine for 1 week repeated every 4 weeks for 12 weeks. Each patient was followed up at weeks 4, 8, and 12.  Efficacy of the continuous treatment group was significantly greater at 76.67% compared with 26.67% in the pulse treatment group. Thus, we conclude that the clinical cure rate of a continuous dose regimen of terbinafine is a superior treatment option for toenail onychomycosis. However, we also suggest further studies including combinations of multiple agents and hybrid regimen models for the optimal onychomycosis treatment.   J Drugs Dermatol. 2023;22(10):     doi:10.36849/JDD.7323R1.

Onychomycosis Treatment Prescribed at Only Twenty Percent of Visits: A Cross-Sectional Analysis of the National Ambulatory Medical Care Survey 2007 to 2016.

BACKGROUND: Onychomycosis represents the highest proportion of nail disorders seen in clinical practice. Onychomycosis management may differ amongst specialties, with impact on patient outcomes and quality of life (QoL). OBJECTIVE: We aimed to characterize onychomycosis treatment across specialties, accounting for patient demographics, to assess for potential onychomycosis practice gaps. MATERIALS/METHODS: We conducted a population based cross-sectional analysis using the National Ambulatory Medical Care Survey (NAMCS) 2007 to 2016 (the most recent years available). RESULTS: Overall, 71.6% of onychomycosis visits were with general practitioners (GPs), 25.8% with dermatologists, and 2.58% with pediatricians. No onychomycosis treatment was prescribed at 82.0% of dermatology visits and 78.9% of GP visits. Dermatologists (Odds Ratio (OR):2.27 [95% Confidence Interval (CI):[2.14-2.41]; P<0.0001) and GPs (OR:2.32 [2.21-2.44]; P<0.0001) were more likely than pediatricians to prescribe treatment vs no treatment. Dermatologists were more likely than GPs to prescribe both no treatment vs treatment and topical vs oral antifungals (OR:1.33 [1.16-1.52]; P<0.0001 and OR:4.20 [3.80-4.65]; P<0.0001), respectively. DISCUSSION: Our study showed that there is a low treatment rate for onychomycosis, with treatment prescribed at only 20% of visits. Untreated onychomycosis might result in secondary infection, pain, and negative QoL impact.1 Although dermatologists are specialists in nail disease management, they saw only about 25% of onychomycosis visits. Future efforts should be directed towards promoting onychomycosis therapy, and educating both patients and referring physicians that dermatologists are primary resources for nail disorder treatment.J Drugs Dermatol. 2023;22(10):1040-1045 doi:10.36849/JDD.6770.

Microbiological culture combined with PCR for the diagnosis of onychomycosis: Descriptive analysis of 121 patients.

BACKGROUND: Onychomycosis is the most common nail pathology, involving various pathogens such as dermatophytes, moulds and yeasts. OBJECTIVE: The objective of this study was to observe the prevalence of onychomycosis, analyse the most appropriate diagnostic test, and assess the distribution of pathogens based on age, sex, quarter of the year, duration of symptoms and previous treatment. METHODS: Retrospectively, mycological culture and PCR data and results were collected from 121 patients. RESULTS: Of the 121 samples, 57% (69/121) tested positive when both microbiological study techniques were combined. The prevalence of onychomycosis was higher when PCR was performed (52.1%) compared to microbiological culture (33.1%). Among the 81 samples negative by microbiological culture, 31 were positive by PCR. Similarly, of the 58 samples negative by PCR, eight were positive by microbiological culture. Diagnostic accuracy data (with 95% confidence intervals) for PCR, using microbiological culture as the gold standard, were as follows: sensitivity of 0.8, specificity of 0.62, positive predictive value of 0.51 and negative predictive value of 0.86. The most frequently identified pathogen was Trichophyton rubrum, and the hallux nail plate was the most commonly affected location. However, no statistically significant associations were found between sex, age, quarter of the year and affected area with culture and PCR results. CONCLUSION: Combining microbiological culture and PCR can increase the detection rate of onychomycosis and help avoid false-negative results.