Last reviewed 11/2022

Koilonychia is dystrophy of the fingernails in which they are thinned and concave with raised edges.

Koilonychia is also described as 'spoon shaped nails' and has the ability to retain a drop of water. The condition is often seen in fingernails and rarely in toenails (1).

This condition may be caused by

  • iron deficiency - most common cause 
  • direct trauma e.g. due to use of vibrating tools.
  • regular contact of hand to petroleum based solvents
  • nail patella syndrome
  • haemachromatosis – occasionally
  • may be a normal nail variant in infants – generally disappear within the first few years in life (1)

Click here for an example image of this condition