Expansion
Clubbing, koilonychia, leuconychia, splinter haemorrhages and pitting
Mnemonic
Each sign points to a system:
- Clubbing - lung (carcinoma, fibrosis, bronchiectasis, empyema), heart (cyanotic disease, endocarditis), gut (inflammatory bowel disease, cirrhosis, coeliac), thyrotoxicosis, and familial
- Koilonychia, spooning - iron deficiency
- Leuconychia, white nails - hypoalbuminaemia
- Beau’s lines, transverse grooves - a severe systemic illness some weeks earlier
- Splinter haemorrhages - trauma most often, but also endocarditis and vasculitis
- Onycholysis - psoriasis, thyrotoxicosis, fungal infection
- Pitting - psoriasis, alopecia areata
- Terry’s nails, white with a distal band - cirrhosis
- Muehrcke’s lines, paired white bands - hypoalbuminaemia
- Mees’ lines, single transverse white - arsenic, chemotherapy
“Schamroth’s window” confirms clubbing: place the nails of the two index fingers back to back, and the normal diamond shaped gap disappears when clubbing is present.
Expansion
| Sign | Appearance | Suggests |
|---|---|---|
| Clubbing | Loss of the nail bed angle, fluctuant bed, drumstick fingers | Lung cancer, bronchiectasis, fibrosis, cyanotic heart disease, endocarditis, IBD, cirrhosis |
| Koilonychia | Spoon shaped | Iron deficiency |
| Leuconychia | White nails | Hypoalbuminaemia: liver disease, nephrotic syndrome, malnutrition |
| Splinter haemorrhages | Linear subungual streaks | Trauma (commonest), infective endocarditis, vasculitis |
| Beau lines | Transverse grooves | Severe systemic illness weeks earlier |
| Onycholysis | Nail lifting from the bed | Psoriasis, thyrotoxicosis, trauma, fungal |
| Pitting | Small depressions | Psoriasis, alopecia areata |
| Terry nails | Proximal white, distal band | Cirrhosis |
| Nail fold infarcts | Vasculitis, connective tissue disease |
Clubbing is assessed by the Schamroth window: normally a diamond-shaped gap appears when the nails of opposing fingers are held together, and it is lost in clubbing.
Beau lines are useful for dating: nails grow at about 0.1 mm per day, so the distance from the cuticle estimates when the illness occurred.