Flash information
- Shape
- Concave, spoon-shaped
- Plate
- Thin or brittle
- Association
- Possible iron deficiency
- Specificity
- No single cause
Definition
Koilonychia describes a flat or concave nail, sometimes with upturned edges.
Examination or reading method
Compare nails frontally and laterally; assess trauma and occupational exposure.
Morphological description
Describe concavity, brittleness and number of affected nails.
Causes and diagnostic direction
Possible causes: iron deficiency, skin disease, trauma or familial predisposition.
Differential diagnoses
Distinguish concavity from ridging, splitting and separation; several plate abnormalities may coexist.
Associated findings
Assess fatigue, pallor, blood loss and gastrointestinal symptoms; blood count and iron testing depend on context.
Red flags
Dysphagia accompanying iron-deficiency anaemia warrants investigation; the nail alone confirms no syndrome.
Pitfalls and limitations
Concavity does not establish deficiency; skin disease and local exposures must also be considered.
Take-home message
Recognise the spoon shape, then investigate a cause compatible with context.
Media source & rights
- Author
- CHeitz
- Original source
- CHeitz — Koilonychia iron deficiency anemia.jpg — CC BY 2.0 — https://commons.wikimedia.org/wiki/File%3AKoilonychia_iron_deficiency_anemia.jpg
- Licence
- CC BY 2.0
- Changes
- Orientation EXIF normalisée ; conversion WebP et redimensionnement proportionnel plafonné à 1600/400px ; aucun recadrage, aucune retouche médicale ; EXIF supprimé. Dérivé écran proportionnel ≤1280 px, WebP qualité76 ; vignette ≤320 px qualité72. Source acquise et dérivé initial conservés sans modification ; aucune retouche médicale, aucun recadrage.
- Dimensions
- 1280 × 799 px
- Check
- 2026-10-11