Rare diseases · Sign or symptom

Nail dystrophy

Poor nail formation

HP:0008404

What it means

Onychodystrophy (nail dystrophy) refers to nail changes apart from changes of the color (nail dyschromia) and involves partial or complete disruption of the various keratinous layers of the nail plate.

Onychodystrophy is a widely used, yet rarely defined term. Onychodystrophy can be caused by congenital nail diseases, systemic disorders, fungal and nonfungal infections, various noninfectious inflammatory dermatologic diseases of the nail unit and tumors. Onychodystrophy can also occur secondarily to systemic drug use.

Rare diseases that can present with this70

Very common80–99%

20

Common30–79%

30

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions, and Orphanet separately records 1 disease where this sign is specifically absent. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category

Also called: Dystrophic nails · Onychodystrophy

Nail dystrophy

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This page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.