What Are Half-Moon Nails, and What Can They Say About Your Health?

Medically Reviewed By Cynthia Cobb, DNP, APRN, WHNP-BC, FAANP

The half-moon shape that can appear on your nails is called the lunula. Changes in its appearance, including color changes, can indicate an underlying condition. The lunula is part of your nail matrix, which is the tissue beneath your nail. The matrix contains blood vessels, nerves, and lymph. The lunula produces the cells that will become your nails once hardened.

While everyone has a nail matrix, the lunula can vary in appearance across your fingers. You may not have a lunula on some nails. Some people do not have a visible lunula on any of their fingers.

This article explains what a healthy lunula looks like, why it can change color and its meaning, and when to contact your doctor.

What does a healthy half-moon on the nail look like?

A person is painting their nails.
Tessy Morelli/Stocksy United

A healthy lunula is usually whitish or a paler tone than the rest of your nails. It is typically easier to spot on your thumb. It takes up a small portion around the base of the nail.

The lunula usually appears smaller on your index and medium finger. Sometimes it is barely visible on your pinkie finger.

What does it mean if the half-moons on my nails change color?

Here are some possible color changes that can happen to the half-moons on your nails and their possible causes.

Blue

If your lunula appears blue, this may be Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source a symptom of Wilson disease. It’s a rare genetic disorder.

People with Wilson disease have an excess amount of copper stored in their tissues. This can lead to liver disease and central nervous system dysfunction.

Learn more about Wilson disease.

Blue-purple

If your lunula appears blue-purple, this can be Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source a symptom of cyanosis. This condition occurs when your blood is not sufficiently oxygenated, or you have poor blood circulation.

Cyanosis can be serious. It is important to seek immediate medical help if your lunulae are blue-purple.

Learn more about cyanosis.

Blue-gray

A blue-gray lunula may be Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source a symptom of argyria or silver poisoning. This can happen due to workplace exposure Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source to silver or as a result of taking silver supplements Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source .

Brown

A brown lunula may be Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source a symptom of severe renal disease or chronic kidney disease.

If you experience chronic kidney disease, the melanin you produce can cause brown coloring. If you have severe renal disease, your nail may also have a half-white and half-brown pattern.

Learn more about chronic kidney disease.

Black

Black discoloration under your nails may be Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source a symptom of malignant melanoma. This is known as Hutchinson’s sign. The discoloration can affect your lunula. It will usually extend down the length of your nail.

Swelling and blood after hitting your nail may also cause a black spot on the lunula.

Learn more about black lines on your nails.

Red

If your lunula appears red, it may be Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source a sign of cardiovascular disease or heart failure. A 2020 study Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source also found a link between red half-moon nails and COVID-19.

Yellow

If you use tetracycline medications to treat acne or skin infections, the lunula on your nail may turn fluorescent yellow.

Your whole nail turns yellow

If your whole nails turn yellow, you may have Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source yellow nail syndrome. People with this condition produce thick and slow-growing nails with a yellow appearance. If you have this condition, the lunula on your nail will disappear and the nail may begin to rise.

There is no clear cause for this syndrome. However, it may have a link with:

Learn more about the causes of yellow nails.

Your whole nail turns white

If you have liver disease, your nails may turn white. If you have kidney disease, they may appear half white and half pink.

You may also Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source experience white nails if you have Terry’s nails. This is a condition that reduces the appearance of your lunulae.

Terry’s nails may also cause a red or pink band near the arc of your nails.

What does it mean if I have small half-moons or no half-moons on my nails?

Small or missing lunulae may not be a cause for concern. They may simply be hidden underneath your cuticle. The cuticle is the part of the skin at the base of your nail.

However, small or missing lunulae may be a sign of other underlying conditions, such as Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source :

What do large half-moons on my nails mean?

A 2018 report Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source found that a person may have large half-moons, or macrolunulae, due to a:

  • hereditary condition
  • systemic disorder
  • benign soft tissue tumor

Contact your doctor if you have concerns about the size of your lunulae or any changes in their shape or size.

When should I contact a doctor?

Missing or discolored half-moons may not be a cause for concern. However, if you notice a change in the nails’ appearance or you’re experiencing other symptoms, contact your doctor for advice.

If your feet and hands are turning blue or purple, seek immediate medical attention. This may be Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source a symptom of cyanosis, a condition that occurs when you have inadequate oxygenation or poor circulation of your blood.

How do doctors diagnose the cause of changes in the half-moons on my nails?

To assist with reaching an accurate diagnosis, your doctor may start by examining the color of your nails, their shape, and their texture. They may also collect a sample from your nails if they suspect any underlying condition.

Your doctor may also recommend other tests for suspected conditions to diagnose the cause of the changes in your nails. These tests will depend on the color of your nails and any other symptoms you have.

Your doctor will be able to explain the tests to you in more detail and answer any questions you may have.

What are the treatments for conditions affecting the half-moons on my nails?

Treatment for the symptoms you may experience on your nails varies depending on the cause.

Some changes in color may be connected to your diet. In these cases, your doctor may give you some recommendations for your nutrition or refer you to a dietitian.

If a medication causes changes in your lunulae, your doctor may review your medication and advise on alternative options.

Other treatments focus on managing the underlying condition. Your doctor will advise on which treatments they recommend. It is important to ask any questions you may have so you can make an informed decision about your treatment plan.

Frequently asked questions

Here are some more frequently asked questions about half-moons on nails.

Should you have a lunula on all fingers?

You may not have a visible lunula on all your fingers. This is because lunulae can hide underneath the skin at the base of your nails.

Are half-moons on nails healthy?

Yes. Half-moons are part of the structure of your nails. Having half-moons is not usually a cause for concern.

Why do I not have a lunula?

Some people do not have visible lunulae. However, this may also be Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source a sign of an underlying condition, such as malnutrition, anemia, or cirrhosis.

What do nails look like with anemia?

Anemia can cause your nails to look pale.

Summary

Your nails can give you information about your nutrition status, cardiovascular system, and overall health. A change in the color of your lunulae may not be concerning.

However, contact your doctor if you notice changes in your nails. They can confirm the cause and advise on any treatments they recommend.

Seek immediate medical advice if your nails turn blue. This can be a sign of cyanosis, which can be serious.

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Medical Reviewer: Cynthia Cobb, DNP, APRN, WHNP-BC, FAANP
Last Review Date: 2022 Nov 30
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