What is a spoon shaped nail?
Sarah Duran
Updated on March 17, 2026
Spoon nails
Koilonychia, also known as spoon nails, is a nail disease that can be a sign of hypochromic anemia, especially iron-deficiency anemia. It refers to abnormally thin nails (usually of the hand) which have lost their convexity, becoming flat or even concave in shape.
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How does iron deficiency cause spoon nails?
Koilonychia occurs in 5.4% of the patients with iron deficiency. It is thought to occur due to the upward deformation of lateral and distal portions of pliable iron deficient nail plates under mechanical pressure. Nail matrix changes due to blood flow abnormalities was also proposed as a pathomechanism.Are spoon nails hereditary?
Spoon nails can also be hereditary (genetic), or caused by your environment. One study of people who lived in a higher altitude found that over 47 percent of them had spoon nails. The study also found that residents who did manual labor had an even higher chance of developing spoon nails.What do fingernails look like with low iron?
Koilonychia is an abnormal shape of the fingernail. The nail has raised ridges and is thin and curved inward. This disorder is associated with iron deficiency anemia. Leukonychia is white streaks or spots on the nails often due to drugs or disease.What causes fingernails to curl on the sides?
Nails that curve around the sidesNails that curve far inward at the sides are called ingrown nails. This condition may affect the toenails and be due to wearing shoes that are too tight, particularly in the toe box. Ingrown nails may also result from cutting the nails improperly.