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ChenDermatologist
ChenDermatologist
Dr. Yi-Jia Chen · Dermatology Patient Education Notes
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Patient guide · Toenail / foot Updated · 2026-05-13

Toenail deformity — visual atlas of 12 patterns
From shoes, foot shape, joints, to diabetes

Dr. Yi-Jia Chen · Synthesis of Ricardo 2026 JAAD review, Haneke 2024 Skin Appendage Disord, Watjer 2024 BMJ Open, Nix 2010 meta-analysis evidence
Bottom line in one sentence:Studies show that More than 90% of toenail dystrophies are not fungal — they are caused by shoe pressure and foot shape. The most common misdiagnosis is onychomycosis (nail fungus), but if foot shape is not addressed, no amount of antifungal treatment cures it. From shoes, foot shape, joints, nerves, vessels, to diabetes — all affect toenails. This guide walks through 12 deformity patterns and their causes in one place.
Note:This article is for general education only and does not replace in-person consultation. Individual treatment must be assessed by a dermatologist or foot-and-ankle specialist based on your specific situation.

Toenail mechanical disorders: a complete patient guide

Over 90% of toenail dystrophy comes from footwear pressure and foot structural problems — not fungus, as patients often assume. This article reviews the 12 most common toenail changes caused by mechanical trauma, the 4 foot deformities most often involved (Morton's toe, hallux valgus, flat foot, splayfoot), special considerations for patients with diabetes, and Taiwan's National Health Insurance coverage of common treatments. Content is summarized from the 2026 JAAD review by Ricardo et al.

The English-language audience may switch to Traditional Chinese via the language toggle for the full article and figure set.