Nail clipping in onychomycosis and comparison with normal nails and ungual psoriasis

Update on nail unit histopathology

Histopathologic evaluation of the nail unit is an essential component in the diagnosis of nail unit disorders. This review highlights recent updates in nail unit histopathology and discusses literature covering a wide range of nail disorders including melanoma/melanocytic lesions, squamous cell carcinoma, onychomatricoma, onychopapilloma, onychomycosis, lichen planus, and other inflammatory conditions. Herein we also discuss recent literature on nail clipping histopathology, a useful and noninvasive diagnostic tool that continues to grow in popularity and importance to both dermatologists and dermatopathologists.

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.

Updates on the Pathology and Management of Nail Unit Tumors and Dermatoses

Nail unit pathology is indispensable to reach an accurate diagnosis of nail tumors as well as inflammatory disorders. This review article provides an update from the most recently published studies on the pathology and management of nail unit tumors and inflammatory disorders. Recent findings of nail clipping histopathology are described first, followed by discussing recent data on the diagnosis and surgical management of several types of nail unit tumors, ending with discussing the recent discoveries in selected nail unit inflammatory disorders.

Subclinical Onychomycosis in Apparently Healthy Adults

Introduction

Onychomycosis is a frequent chronic nail infection, with a worldwide prevalence of 5.5% making it the most common nail disease, and its incidence increases with age. Clinically, it causes discoloration and thickening of the nail plate and may be accompanied by onycholysis. However, little is known of the subclinical infection.

Methods

We studied adult male and female outpatients auto-referred as healthy and that had healthy appearing toenails. Nail distal clippings were obtained from the right first toenail. This sample was stained with PAS and observed by an expert dermatopathologist searching for fungal structures.

Results

A total of 32 samples were included: 8 from men (25%) and 24 from women (75%), with ages ranging from 27 to 66 years (mean age of 43 years). Twenty-four patients did not present any histopathological finding suggestive of infection (75%), while 7 patients had a single finding (spores or hyphae) (21.8%), and 1 patient had both findings (3.12%).

Discussion/Conclusion

We found 4 patients with yeasts, 3 with hyphae, and 1 patient with a combined infection with both yeasts and hyphae (3.1%). These add up to 25% of the clinically apparent healthy nails. Our results show that we still have much to learn from the initial stages of onychomycosis and that our population probably has higher incidence of this nail disease, so we must be alert to subtle nail changes. As our participants signed an informed consent, we will contact those that resulted positive for follow up consultations.