# Onychomycosis Endonyx: A Systematic Review

## TL;DR

This paper reviews endonyx onychomycosis, a rare nail infection, and finds inconsistencies in diagnosis and reporting across studies.

## Contribution

The study systematically reviews and highlights diagnostic inconsistencies in endonyx onychomycosis cases reported globally.

## Key findings

- 28 articles with 175 patients diagnosed with endonyx onychomycosis were identified, mainly from Asia and Africa.
- Only 47.3% of the studies provided a consistent definition of endonyx onychomycosis.
- Multiple fungal agents, including Trichophyton and Fusarium species, were reported as causative agents.

## Abstract

Background/Objectives: Endonyx onychomycosis is a chronic infection of the nail plate that presents as milky white discoloration, without hyperkeratosis or onycholysis, and was originally described as being caused by T. soudanense and T. violaceum. Methods: In the present review, the definitions used in the different articles and the clinical characteristics of patients diagnosed with this onychomycosis variant were analyzed through a systematic review of the reported cases in the literature using the terms “endonyx” AND “onychomycosis” in PUBMED, SciELO, SCOPUS, Web of Science, and Google Academics databases. Results: We found 28 articles with a total of 175 patients diagnosed with endonyx onychomycosis, mainly reported in Asia and Africa. Nine papers presented detailed descriptions. From these, a total of 15 immunocompetent patients were registered, and the etiological agents reported were Trichophyton soudanense, T. rubrum, T. violaceum, T. tonsurans, and Fusarium spp. After analyzing the definitions employed in the remaining articles, only 47.3% cited or described a concept consistent with the original description. The other 47.3% of the studies lacked a traceable criterion for the diagnosis of these cases. Moreover, most studies analyzed their data at a global level, describing little information to provide specific insights into the endonyx variant. Conclusions: Emphasis on clinical description and histopathological analysis is essential to confirm the role of less commonly reported fungi, and more accurate diagnostic and treatment protocols for this condition are mandatory.