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.

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.