Fingernails: The Crystal Balls of Health

Fingernails can show signs of many common diseases and conditions

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

Some people think of fingernails as a fashion accessory, while others barely give them any thought at all. But your fingernails can be an impressive gauge of your overall health.

We paint them, chew on them, and occasionally break them. Fingernails help us hang on and get a grip. They scratch our worst itches, and make some of us cringe when they meet a chalkboard. For all they do, we may not give fingernails much thought.

Fingernails have several main parts:

  • Matrix: The area where new nail plate cells are created and the nail plate begins.
  • Eponychium: The living cells at the base of the nail plate that covers the matrix area.
  • Cuticle: A thin layer of dead skin that provides a protective layer between the nail plate and the eponychium to help block pathogens and prevent infection of the matrix.
  • Nail Plate: The hard portion of the nail and the part you clip and paint.
  • Lunula: The white curved area at the base of the nail, most easily seen on the thumbs.
  • Nail Bed: The pink skin beneath the nail where it attaches to the finger.

For all of their convenient uses, fingernails give us a terrific look into what ails us. Here are a few fingernail abnormalities you should pay attention to.


Nails that appear to float above the nail bed and make the end of the fingers appear large or bulging are known as clubbing nails. Clubbing of the nails, also called drumstick finger, can be a sign of lung problems like emphysema that cause low levels of oxygen in the blood.

Nail clubbing has also been linked to inflammatory bowel disease, cardiovascular disease, liver disease and AIDS.


Nails that begin to concave and look like scoops or spoons can be an indication of iron deficiency anemia or hemochromatosis, a condition in which iron builds up in the organs, especially the liver. Spoon nails can also be a sign of heart disease and hypothyroidism, a condition in which the thyroid fails to create normal levels of certain important hormones.

Terry’s Nail

Terry’s nail can be identified by a thick, dark band at the tip of each finger, just behind the white area at the free edge of the nail plate. Terry’s nail can sometimes be attributed to old age, but it is often a sign of liver disease, congestive heart failure or diabetes.

Beau's Lines

Beau’s lines are indentations that run across the nail, from side to side. Beau’s lines can be caused by injury under the cuticle or by severe illness, such as scarlet fever, measles or mumps. It can also be a sign of uncontrolled diabetes and peripheral vascular disease, a condition caused by blockage of an artery outside the brain or heart.

Yellow Nail Syndrome

Yellowish, discolored nails that can detach from the nail bed or lack a cuticle are a sign of yellow nail syndrome. Yellow nail syndrome can be caused by swollen hands, but also can be a sign of respiratory disease, such as chronic bronchitis.

Streaking or dark spots

Dark streaks or spots as well as long cracks, in or under the nails, can be a sign of a melanoma, a form of skin cancer. These symptoms should be taken seriously, especially if it doesn’t heal normally.

"Most people do not think of skin cancer occurring in the nail area, yet it very well may. Subungual (under the nail) melanoma may occur in all skin types especially more deeply pigmented individuals,” said dermatologist Dr. Coyle S. Connolly, president of Connolly Dermatology in New Jersey. “One should report any non-healing area or changing/new dark spot or streak to their dermatologist."


Not all fingernail abnormalities are a sign of a problem, according to the Mayo Clinic. For example, white spots in your nails are not a sign of calcium or zinc deficiency, despite the common myth that makes this claim. White spots in the nail are most commonly a sign of an impact or pressure on the nail.

Understanding what your fingernails are telling you can help you get treatment for underlying health problems before they become more severe. Discuss any changes in the appearance of your fingernails with your doctor and make a point to practice good nail care with regular trimming and cleaning.

Review Date: 
May 12, 2014
Last Updated:
May 16, 2014