Beau’s Lines

Beau’s lines are horizontal indentations or ridges across the nail. They can develop on the fingernails and toenails and are caused by illness, injury, or infection. 

This article discusses the symptoms, causes, and treatment options for Beau’s lines.

Symptoms of Beau’s Lines

The main symptom of Beau’s lines is the ridge that appears in the nail. The nail may also become discolored and appear yellow, like the color changes that occur in fungal infections. Other symptoms can develop depending on the cause. Since there are many causes, the symptoms will vary drastically.

Causes of Beau’s Lines

The exact cause of Beau’s lines isn’t well understood, but it develops when the nail growth from underneath the cuticle is interrupted. However, many diseases and infections can cause the nail to stop growing as it should, leading to Beau’s lines. Injuries and environmental factors also play a role in developing indentations in the nails. They are almost always caused by these outside stressors.

Some possible conditions and infections that cause the ridges to develop in the nails include:

• Diphtheria
• Syphilis
• Measles
• Mumps
• Malaria
• Typhoid fever
• Scarlet fever
• Hand-foot-mouth disease
• Sepsis
• Rheumatic fever
• Myocardial infarction (heart attack)
• Uncontrolled diabetes
• Postpartum hyperparathyroidism
• Telogen effluvium
• Raynaud’s disease 
• Pneumonia
• Coronary thrombosis (a blockage in the heart)
• Kawasaki disease
• Autoimmune diseases

Injuries can also play a role in the development of Beau’s lines, including:

• Picking at the nails and cuticles repeatedly
• Manicures or pedicures
• Temporary reduction in blood flow due to trauma of the hand, wrist, or elbow
• Nerve injuries that occur after fractures or carpal tunnel syndrome
• Being in a cast or splint for a broken finger, hand, or wrist 
• Major surgeries

Environmental and lifestyle factors can also lead to Beau’s lines, such as:

• Psychological stress
• Exposure to extreme cold temperatures
• Malnutrition or nutrient deficiencies

What Medications Can Cause Beau’s Lines?

Several medications have been tied to Beau's lines, especially chemotherapy drugs. When you undergo chemo treatment, you will likely notice Beau's lines on your fingernails and toenails. The lines will also develop relatively quickly after treatment begins, such as within two to three weeks of starting chemotherapy.

Chemotherapy drugs cause Beau's lines by affecting the cells with a high turnover rate, such as those below the cuticle, where nails start growing (nail matrix). The cells reproduce slower, thus, slowing down the growth of the nail and causing the ridges.

How to Treat Beau’s Lines

There is no one treatment for Beau’s lines, and therapy revolves around treating the cause, so treatment will depend on the underlying cause.

Once treatment for the underlying cause has commenced, Beau’s lines typically clear up within three to six months, which is generally how long it takes for the nail to regrow so the ridge can be cut off entirely. If caused by chemotherapy, it will take the same amount of time once chemotherapy has been completed.

Are There Tests to Diagnose the Cause of Beau’s Lines?

Diagnosing Beau’s lines is simple because it can be done through physical examination. That said, diagnosing the cause is more complicated and needs to be done before any treatment can begin. The tests used to diagnose what is causing Beau’s lines will depend entirely on other symptoms you are experiencing and your health history and current state of health.

Summary

Beau's lines are horizontal dents in the nails. They can be caused by diseases, injuries, or infections. Because there are many causes, it can be hard to determine the treatment options until a diagnosis is made. If you notice the indentations in your nails and are not undergoing chemotherapy, speak to your healthcare provider to determine the cause and your treatment options.