Diagnosis of Onychomycosis: From Conventional Techniques and Dermoscopy to Artificial Intelligence

Abstract

Onychomycosis is a common fungal nail infection. Accurate diagnosis is critical as onychomycosis is transmissible between humans and impacts patients' quality of life. Combining clinical examination with mycological testing ensures accurate diagnosis. Conventional diagnostic techniques, including potassium hydroxide testing, fungal culture and histopathology of nail clippings, detect fungal species within nails. New diagnostic tools have been developed recently which either improve detection of onychomycosis clinically, including dermoscopy, reflectance confocal microscopy and artificial intelligence, or mycologically, such as molecular assays. Dermoscopy is cost-effective and non-invasive, allowing clinicians to discern microscopic features of onychomycosis and fungal melanonychia. Reflectance confocal microscopy enables clinicians to observe bright filamentous septate hyphae at near histologic resolution by the bedside. Artificial intelligence may prompt patients to seek further assessment for nails that are suspicious for onychomycosis. This review evaluates the current landscape of diagnostic techniques for onychomycosis.

Transmission of Onychomycosis and Dermatophytosis between Household Members: A Scoping Review

“…One study found dermatophytosis to be asymptomatic in 16% of children [64], and another found dermatophyte carriage in 86% of family members with one affected child with tinea pedis [65]. Recent advances in the diagnosis of onychomycosis may facilitate the detection of cases in asymptomatic individuals in order to better characterize patterns of transmission among household members [66].…”

Evaluation of different DNA extraction methods based on steel‐bullet beating for molecular diagnosis of onychomycosis

“…An accurate diagnosis of onychomycosis is an important prerequisite for proper and successful treatment. Molecular biology tools are increasingly being used to overcome the poor diagnostic sensitivities and long turnaround times associated with the detection and identification of fungal pathogens in clinical samples such as nails 7 . Application of different methods of sample storage and collection, DNA extraction, sequencing library preparation, and bioinformatics analysis has been shown to contribute variability to the results of molecular studies.…”

Diagnosing Onychomycosis: What’s New?

“…Nail dystrophy associated with infection may also be visible. Histopathology is reportedly the most sensitive of the conventional onychomycosis diagnostic methods; however, as with KOH, it does not provide the identity or viability of the organism [ 9 , 10 ]. Submission of a nail plate alone may not detect nail bed infection.…”

“…The technology can provide sharper resolutions and more-detailed structure of objects versus standard light microscopy [ 32 ]. It is non-invasive [ 3 , 33 ] and can examine a nail directly in the office in real-time (5–10 min), making it a quick evaluation method [ 10 , 34 , 35 ]. The technique does have a limited depth of penetration, varying based on scanning laser wavelength, and only moderate levels of sensitivity and specificity have been reported [ 10 , 36 , 37 ].…”

“…It is non-invasive [ 3 , 33 ] and can examine a nail directly in the office in real-time (5–10 min), making it a quick evaluation method [ 10 , 34 , 35 ]. The technique does have a limited depth of penetration, varying based on scanning laser wavelength, and only moderate levels of sensitivity and specificity have been reported [ 10 , 36 , 37 ]. Confocal microscopy can provide direct imaging of fungal structures suggestive of onychomycosis, showing as bright filamentous septate hyphae [ 23 , 33 ] ( Figure 1 F).…”