Koilonychia (Spoon Nails)

By Joseph Constance BA, MA

The appearance of the human nail can be an indicator of one’s overall health status. Besides revealing a nail infection or injury, unusual characteristics of a fingernail or toenail can be indications of an underlying systemic condition. Nail irregularities can result from conditions involving single organs or several systems or organs. They can also be caused by drug intake.

Spoon nail - Image Copyright: / Shutterstock
Spoon nail - Image Copyright: / Shutterstock


There are many signs or symptoms of nail conditions, such as changes in the skin, hair or nail color, changes in the growth or growth rate of the nails, vascular alterations, periungual warts that appear around the nail, and textural disorders. Just about any component of the nail can be impacted by nail disease, including the cells at the base of the nail, the hard translucent portion of the nail, the bed, any part of the nail’s vascular system, and the related tissue or membrane. The significance of the injury caused by the condition and its location dictate how the defect appears.

A person may have the medical condition known as koilonychia if their toenails or fingernails turn to the inside as a spoon is shaped.

Associated medical conditions

If a patient has koilonychia, then they could have any of several underlying conditions, including:

  • Iron-deficient anemia, in which a shortage of iron content in the body leads to a decreased number of red blood cells.
  • Iron overload, which could be an inherited condition, or which could result from receiving transfusions of blood.
  • A physical injury or trauma.
  • The blockage of blood in the vessels.
  • The autoimmune disease lupus.  
  • Nail patella syndrome, a genetic disorder that causes underdeveloped small nails.
  • Excessive stress.

Some researchers have observed that fungus, inflammation and redness, or injury may be at the heart of an individual’s koilonychia. The curving inward of the nail that occurs may be caused by the angling position of the layer of cells in the nail bed that results from alterations in surrounding tissue.

Continuous exposure to solutions that are petroleum-based, as well as to soaps and detergents also may contribute to the onset of koilonychia. The inability of the intestine to correctly uptake the nutritional components of foods also can lead to the condition.

Sometimes, changes in the appearance of the nail may not indicate an underlying health condition. For instance, old age will make a nail drier and more rigid. Koilonychia can sometimes be a normal variation of the nail in infants, and will often correct itself within a few years.

Diagnosis and treatment

If koilonychia is tied into an underlying condition, then treating that condition should correct the spooning. When spooning appears and a related condition cannot be found, a complete blood count and ferritin level must be obtained. These tests will determine if there is too much or too little iron in the system. However, some cases may remain unknown and not have any implications for patients.

Essentially, when a patient presents with koilonychias, a thorough search for a cause must be made, so as to eliminate any serious underlying conditions and to reassure the patient that the condition is minor, although annoying.

Reviewed by , BPharm

Further Reading

Last Updated: Oct 12, 2016

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