July 22, 2024


Built General Tough

Beau’s Lines on Nails: Causes, Pictures, and Treatment

Most people don’t pay much attention to their fingernails on a regular basis. Yet our fingernails are a big help to us in our everyday lives: They help us grip, scratch, separate things, and much more.

You might also be surprised to learn that the appearance of your fingernails can help you better understand you health. And in some cases, our nails may pinpoint specific health problems.

One common nail deformation often indicating health trouble is Beau’s lines. Sometimes people mistakenly call these ridges forming across the nail “bows lines,” or “bow lines.”

Beau’s lines occur when nail growth is interrupted at the nail matrix — the place where your nail emerges from your finger.

Usually the cause of Beau’s lines is injury or severe illness, but in some cases, environmental factors may be to blame. In order to treat Beau’s lines, you must treat the underlying medical condition that caused them.

Beau’s lines are horizontal indentations, or ridges, that develop across the nails. They usually run straight across the nail. A person may develop one or more Beau’s lines on any nail, or across multiple nails.

Beau’s lines can develop as a result of injuries, illnesses, or environmental factors such as:

  • picking at the nails or cuticles
  • getting an infection around the edge of the nail
  • getting a manicure

The appearance of Beau’s lines may offer insight into their cause. More than one line on one of your nails is usually a sign of repeated external injury to the nail matrix or an infection.

However, if you have more than one nail with Beau’s lines, the cause is likely a systemic illness, prolonged exposure to certain environmental factors, or chronic disease.

Some of the most common causes include:

Acute kidney failure

Acute kidney failure is a term used to describe what happens when the kidneys rapidly shut down, usually in a period of 2 days or less. This condition is serious and requires emergency medical attention.

Acute kidney disease can affect anyone, but you’re more likely to experience this condition if you:

  • are 65 or older
  • already have kidney disease or a kidney issue
  • have high blood pressure
  • have a chronic disease, like heart disease, liver disease or diabetes
  • have peripheral artery disease

If you have acute kidney disease, you may have:

  • problems with urination
  • pain in your chest
  • confusion
  • swelling in your lower extremities
  • lethargy
  • nausea

Severe kidney disease may cause seizures or coma.


Mumps is a highly contagious virus affecting the salivary glands located near your ears. If you have mumps, you may notice that one or both of these glands are swollen.

Complications from mumps are rare but possible and may affect the reproductive system, pancreas, brain, ears, heart, and spinal cord.

Mumps was once common in the United States but has become less so, thanks to widespread vaccination campaigns.

Thyroid disease

The term thyroid disease is used to describe issues relating to the function of hormones produced by the body’s thyroid gland. These hormones regulate everything from growth to metabolism.

Various thyroid disorders may contribute to the formation of Beau’s lines, including:

Often, people with thyroid issues experience issues related to weight, anxiety, energy level, and tolerance of cold and heat.


Syphilis is a kind of bacterial infection that’s usually passed from person to person during sexual activities or from a mother to unborn child.

This infection starts out as one or a few sores, usually erupting on the genitals, rectum, or mouth. Eventually, a rash covers the whole body, though it will go away again before remaining inactive. It could take decades for the infection to become active again.

Usually penicillin can successfully clear an early case of syphilis. If left untreated, syphilis can cause serious damage to the heart, brain, and other organs. It can even result in death.

Side effect of chemotherapy

It’s common for chemotherapy to interrupt and temporarily impair proper nail growth from the nail matrix. This can result in Beau’s lines forming.


Endocarditis is the term used to refer to the swelling of the heart’s inner lining. The lining is called the endocardium. Often this swelling is the result of an infectious bacteria.


Subungual melanoma is a type of melanoma affecting the nails that can disrupt nail growth at the nail matrix. It’s extremely rare.

A common sign of subungual melanoma is discoloration of the nail — the nail may have a brown stripe or section.


People with diabetes must be sure to monitor their blood sugar and dose themselves with insulin. If blood sugar rises too high, a person can experience various health complications, from nerve damage to heart disease. It can also interrupt nail growth.


Pneumonia is a type of lung infection that causes swelling of the lung’s air sacs. The sacs may fill with fluid or pus. This leads to:

  • coughing with phlegm or pus
  • fever
  • chills
  • trouble breathing

Pneumonia can be caused by bacteria, viruses, or fungi.

Scarlet fever

Scarlet fever is an illness that sometimes affects people who have strep throat.

People who develop scarlet fever experience a bright red rash covering much of the body. It usually occurs along with a sore throat and high fever and often affects younger children and teens.

If left untreated, it can cause major bodily problems affecting the heart, kidneys, and other body parts.

Zinc deficiency

Zinc is a mineral found in many foods in our diet, from oysters to beans. A lack of zinc in the body may be caused by a poor diet or other factors.

People who don’t consume enough zinc may experience:

  • delayed growth and development
  • loss of appetite
  • poor immune function

There are several kinds of disorders affecting the nails, and more specifically causing lines similar to Beau’s lines to form.

A black line on the nails is known as a splinter hemorrhage. It can be caused by local trauma, such as getting your finger stuck in a door, or a medical illness like endocarditis or psoriasis.

Another kind of line, which can be black or brown, is known as melanonychia. This condition may be the harmless coloration of your nail. It could be the sign of a health issue, such as trauma or infection.

Terry’s nails is a condition causing nails to be all white with a small line of pink or brown at the end. They commonly affect people with liver disease.

Nails that look half light and half dark are called Lindsay’s nails. These are linked to liver disease.

White spots on the nails are known as leukonychia. It’s a common harmless issue caused by injury to the nail matrix, frequent manicures, or use of acrylic nails.