Health Illustrated Encyclopedia

Nail abnormalities


Nail abnormalities are problems with the color, shape, texture, or thickness of the fingernails or toenails.

Alternative Names

Beau's lines; Fingernail abnormalities; Spoon nails; Onycholysis; Leukonychia; Koilonychia; Brittle nails


Just like the skin, the fingernails tell a lot about your health.

Pitting is the presence of small depressions on the nail surface. Pitting nails are often accompanied with crumbling of the nail. The nail can becomes loose and sometimes fall off.

Ridges are tiny, raised lines (linear elevations) that develop across or up and down the nail.

Beau's lines are linear depressions that occur sideways (across) on the fingernail. These lines can occur after illness, injury to the nail, and when you are malnourished.

Leukonychia is white streaks or spots on the nails.

Koilonychia is an abnormal shape of the fingernail where the nail has raised ridges and is thin and concave. This disorder is associated with iron deficiency anemia.

Brittle nails are often a normal result of aging, but may also be due to certain diseases and conditions.



  • Crushing the base of the nail or the nail bed may cause a permanent deformity.
  • Chronic picking or rubbing of the skin behind the nail can cause a washboard nail.
  • Long-term use exposure to moisture or nail polish can cause nails to peel and become brittle.


  • Fungus or yeast cause changes in the color, texture, and shape of the nails.
  • Bacterial infection may cause a change in nail color or painful areas of infection under the nail or in the surrounding skin. Severe infections may cause nail loss.
  • Viral warts may cause a change in the shape of the nail or ingrown skin under the nail.
  • Certain infections (especially of the heart valve) may cause splinter hemorrhages (red streaks in the nail bed).


  • Disorders that affect the amount of oxygen in the blood (such as abnormal heart anatomy and lung diseases including cancer or infection) may cause clubbing.
  • Kidney disease can causes a build-up of nitrogen waste products in the blood, which can damage nails.
  • Liver disease can damage nails.
  • Thyroid diseases including hyperthyroidism or hypothyroidism may cause brittle nails or splitting of the nail bed from the nail plate (onycholysis).
  • Severe illness or surgery may cause horizontal depressions in the nails (Beau's lines).
  • Psoriasis may cause pitting, splitting of nail plate from nail bed (onycholysis), and chronic destruction of the nail plate (nail dystrophy)
  • Other conditions that can affect the appearance of nails include systemic amyloidosis, malnutrition, vitamin deficiency, and lichen planus.


  • Arsenic poisoning may cause white lines and horizontal ridges.
  • Silver intake can cause a blue nail.

When to Contact a Medical Professional

If you have pale nails, clubbed nails, blue nails, distorted nails, white lines and horizontal ridges, or a white color under the nails, consult your health care provider to determine the proper way to treat the underlying cause of the problem.

If you have splinter hemorrhages, see the doctor immediately!

What to Expect at Your Office Visit

The health care provider will look at your nails and ask questions about your symptoms. Questions may include:

  • Type
    • What is the abnormality?
    • Are the nails an abnormal color?
      • What color are they?
      • Are there red lines running the length of the nail (splinter hemorrhage)?
    • Are they an abnormal shape?
    • Has the texture changed?
    • Has the thickness changed?
    • Are the nails pitted?
    • Are the nails detached?
    • Are there ridged nails?
      • Which direction does the ridging go?
    • Does the whole end of the finger look enlarged?
    • Is there a lack of luster?
    • Are the nails brittle?
  • Location
    • Is it the hands?
    • Is it the feet?
    • Is it only on one side?
    • Are both sides the same?
    • Is it only one specific nail?
  • Aggravating factors
    • Have you had an injury to the nail?
    • Do you bite your nails?
    • Do you pick your nails or rub the fingers or toes chronically?
    • Are the nails frequently moist?
    • Do you use nail polish?
  • Other
    • What other symptoms are also present?

Diagnostic tests will depend on what other symptoms, if any, exist. These may include x-rays, blood tests, or examination of parts of the nail in the laboratory.


Do not bite, pick, or tear at your nails. In severe cases, some people may need psychological help or encourage to stop these behaviors.

Keep hangnails clipped.

Wear shoes that don't squeeze the toes together, and always cut the nails straight across along the top.

To prevent brittle nails, keep the nails short and avoid nail polish. Use an emollient (skin softening) cream after washing or bathing.

The vitamin biotin and clear nail polish that contains protein can help strengthen your nails.

Provided by

Review Date: 4/12/2007
Reviewed By: Kevin Berman, MD, PhD, Associate, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network.
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