What are nail abnormalities?

Healthy nails appear smooth and have consistent coloring. As you age, you may develop vertical ridges, or your nails may be a bit more brittle. This is harmless. Spots due to injury should grow out with the nail.

Abnormalities — such as spots, discoloration, and nail separation — can result from injuries to the fingers and hands, viral warts (periungual warts), infections (onychomycosis), and some medications, such as those used for chemotherapy.

Certain medical conditions can also change the appearance of your fingernails. However, these changes can be difficult to interpret. Your fingernails’ appearance alone isn’t enough to diagnose a specific illness. A doctor will use this information, along with your other symptoms and a physical exam, to make a diagnosis.

You should always consult your doctor if you have any questions about changes in your nails.

Abnormalities of the fingernail

Some changes in your nails are due to medical conditions that need attention. See your doctor if you have any of these symptoms:

  • discoloration (dark streaks, white streaks, or changes in nail color)
  • changes in nail shape (curling or clubbing)
  • changes in nail thickness (thickening or thinning)
  • nails that become brittle
  • nails that are pitted
  • bleeding around nails
  • swelling or redness around nails
  • pain around nails
  • a nail separating from the skin

These nail changes can be caused by a variety of different conditions, including ones we describe below.

Beau’s lines

Depressions that run across your fingernail are called Beau’s lines. These can be a sign of malnourishment. Other conditions that cause Beau’s lines are:

  • diseases that cause a high fever such as measles, mumps, and scarlet fever
  • peripheral vascular disease
  • pneumonia
  • uncontrolled diabetes
  • zinc deficiency

Clubbing is when your nails thicken and curve around your fingertips, a process that generally takes years. This can be the result of low oxygen in the blood and is associated with:

  • cardiovascular diseases
  • inflammatory bowel disease
  • liver diseases
  • pulmonary diseases
  • AIDS
Koilonychia (spooning)

Koilonychia is when your fingernails have raised ridges and scoop outward, like spoons. It’s also called “spooning.” Sometimes the nail is curved enough to hold a drop of liquid. Spooning can be a sign that you have:

  • iron deficiency anemia
  • heart disease
  • hemochromatosis, a liver disorder that causes too much iron to be absorbed from food
  • lupus erythematosus, an autoimmune disorder that causes inflammation
  • hypothyroidism
  • Raynaud’s disease, a condition that limits your blood circulation
Leukonychia (white spots)

Nonuniform white spots or lines on the nail are called leukonychia. They’re usually the result of a minor trauma and are harmless in healthy individuals. Sometimes leukonychia is associated with poor health or nutritional deficiencies. Factors can include infectious, metabolic, or systemic diseases as well as certain drugs.

Mees’ lines

Mees’ lines are transverse white lines. This can be a sign of arsenic poisoning. If you have this symptom, your doctor will take hair or tissue samples to check for arsenic in your body.


When the nail plate separates from the nail bed, it causes a white discoloration. This is called onycholysis. This can be due to infection, trauma, or products used on the nails.

Other causes for onycholysis include:

  • psoriasis
  • thyroid disease

Pitting refers to small depressions, or little pits, in the nail. It’s common in people who have psoriasis, a skin condition that causes the skin to be dry, red, and irritated. Some systemic diseases can also cause pitting.

Terry’s nails

When the tip of each nail has a dark band, it’s called Terry’s nails. This is often due to aging, but it can also be caused by:

  • congestive heart failure
  • diabetes
  • liver disease
Yellow nail syndrome

Yellow nail syndrome is when the nails get thicker and don’t grow as fast as normal. Sometimes the nail lacks a cuticle and may even pull away from the nail bed. This can be the result of:

  • internal malignancies
  • lymphedema, swelling of the hands
  • pleural effusions, fluid buildup between the lungs and chest cavity
  • respiratory illnesses such as chronic bronchitis or sinusitis
  • rheumatoid arthritis

These are just some of the signs of abnormal fingernails. Having any of these signs isn’t proof of any medical condition. You’ll need to visit your doctor to determine if your condition is serious. In many cases, proper care of your nails is enough to correct their appearance.

How to care for your nails

You can prevent many nail abnormalities by taking good care of your nails. Follow these general guidelines to keep your nails healthy:


  • Don’t bite or tear at your nails, or pull on hangnails.
  • Always use nails clippers and trim them after you bathe, when nails are still soft.
  • Keep your nails dry and clean.
  • Using sharp manicure scissors, trim your nails straight across, rounding the tips gently.

If you have a problem with brittle or weak nails, keep them short to avoid breakage. Use lotion on your nails and cuticles to keep the nail and nail beds moisturized.


If you get professional manicures or pedicures, make sure your nail salon is properly certified and that nail technicians use proper sterilization techniques. You should avoid long-term use of nail polish and nail polish removers.


Consult your doctor if you notice a problem with your nails to rule out any serious conditions.