You probably glance at your fingernails more than almost any other part of your body. Most of us only notice when a nail chips or a polish needs a touch-up. But the surface of a nail can carry small clues your doctor is trained to spot.
Checking your nails is a standard part of a physical exam, according to the Cleveland Clinic. Color, shape, texture and small lines under the nail can all point to conditions ranging from iron deficiency to heart, lung and liver problems.
None of these signs diagnose anything on their own. But a change that lasts for weeks is worth mentioning at your next check-up.
Pale or very white nails
Very pale nails may be a sign of anemia, congestive heart failure, liver disease or poor nutrition, according to Scripps Health. If your nail beds also look paler than usual compared with your palms, flag it at your next visit.
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Yellow nails that stop growing
Most yellow nails are harmless. Smoking, dark polish and a common fungal infection are the usual culprits, Cleveland Clinic notes.
Yellow nail syndrome is different. The nails grow very slowly, thicken and turn yellow. University of Utah Health links it to lung disease such as bronchiectasis, a condition in which the airways widen and fill with mucus.
Persistent yellowing with no obvious cause is worth a doctor visit, particularly if you also have a chronic cough.
Blue nail beds
If the skin under your nails has a bluish tint, your body may not be getting enough oxygen, according to Scripps Health. It can point to lung disease or a heart problem, and should be checked promptly.
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A dark line running down a nail
A new dark brown or black streak that runs the length of a single nail is the change dermatologists take most seriously.
The American Academy of Dermatology advises seeing a board-certified dermatologist for a skin cancer check, because the streak can be a sign of melanoma under the nail.
This one you do not wait on. Any new or changing dark line in a nail is worth a prompt appointment.
Spoon-shaped nails
Fingernails that dip in the middle and look scooped out, known as koilonychia, are a classic sign of iron deficiency, according to the AAD. Scripps adds that they can also point to an underactive thyroid or a liver problem.
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If your spoon nails come with fatigue, a pale face and brittle hair, a simple blood test can check your iron levels.
Clubbing of the fingertips
Clubbing is a slow, spherical curving of the fingertips, where the nails wrap down over the end of the finger. University of Utah Health links it to lung disease, heart disease, thyroid disease or infection.
It usually develops over years, so a recent change is more telling than a lifelong one.
Pitting on the nail surface
Small dents that look like they were made with the tip of a pin may be a sign of psoriasis, a common skin condition, Cleveland Clinic explains. The AAD also links pitting to atopic dermatitis and to alopecia areata, an autoimmune condition that affects hair.
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Horizontal ridges across the nail
Deep lines that run side to side across the nail are called Beau's lines. According to Scripps Health, they signal a pause in nail growth and can follow a high fever, a serious infection, a vitamin deficiency, or conditions such as diabetes.
When to call your doctor
Nail changes alone do not diagnose anything, and most of what you see in the mirror is harmless. A one-off white spot or a chipped nail is almost never a warning sign.
What matters is a change that is new, persistent or growing. A dark streak that was not there last month, a yellow nail that will not grow out, or a slow curving of the fingertips over the past year all belong on the list you bring to your doctor.
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This article is made and published by Mie Hermansen, who may have used AI in the preparation.