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Nail abnormalities

  • Definition

    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.

    • Beau's lines are depressions across the fingernail. These lines can occur after illness, injury to the nail, and when you are malnourished.
    • Brittle nails are often a normal result of aging. However, they also may be due to certain diseases and conditions.
    • 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.
    • Pitting is the presence of small depressions on the nail surface. Sometimes the nail is also crumbling. The nail can become loose and sometimes falls off.
    • Ridges are tiny, raised lines that develop across or up and down the nail.

    Common Causes


    • 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 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 red streaks in the nail bed ( splinter hemorrhages).


    • 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 cause a build-up of nitrogen waste products in the blood, which can damage nails.
    • Liver disease can damage nails.
    • Thyroid diseases such as 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 the nail plate from the nail bed, and chronic destruction of the nail plate (nail dystrophy).
    • Other conditions that can affect the appearance of the nails include systemic amyloidosis, malnutrition, vitamin deficiency, and lichen planus.
    • Skin cancers near the nail and fingertip can distort the nail. Subungal melanoma is a potentially deadly cancer that will normally appear as a dark streak down the length of the nail.
    • Darkening of the cuticle associated with a pigmented streak may a sign of an aggressive melanoma.


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


    • Certain antibiotics can cause lifting of the nail from the nail bed.
    • Chemotherapy medicines can affect nail growth.

    Normal aging affects the growth and development of the nails.