What Causes Blue Fingernails?

Medically reviewed by Nancy L. Moyer, MD on March 29, 2018Written by J. C. Jones, MA, RN

Blue fingernails are caused by a low level or lack of oxygen circulating in your red blood cells. This condition is known as cyanosis. It occurs when there isn’t enough oxygen in your blood, making the skin or membrane below the skin turn a... Read More

Blue fingernails are caused by a low level or lack of oxygen circulating in your red blood cells. This condition is known as cyanosis. It occurs when there isn’t enough oxygen in your blood, making the skin or membrane below the skin turn a purplish-blue color.

The discoloration of the skin could also represent a high level of an abnormal form of hemoglobin in the blood that’s circulating throughout your body. Hemoglobin is the protein responsible for transporting the oxygen in your blood.

Cold temperatures can also cause your fingernails to turn blue. That’s because cold temperatures force your blood vessels to constrict. The narrow pathways make it difficult for the right amount of oxygen-rich blood to get to your nails.

If normal nail color returns upon warming up or massaging your hands, the blue color was likely due to the that part of your body not getting enough blood supply because of cold temperatures.

Blue fingers due to cold temperatures is a normal response of the body in order to keep internal organs at the right temperature.

However, if fingernails remain blue, there may be an underlying disease or structural abnormality interfering with the body’s ability to deliver oxygenated red blood throughout.

Conditions that cause blue fingernails

Blue discoloration of your fingernails can be caused by problems in the lungs, heart, blood cells, or blood vessels. A list of conditions that can cause cyanosis include the following.

Diseases of the lungs

Diseases of the heart

Abnormal blood cells

Abnormal blood vessels

Diagnosis and treatment of cyanosis

A noninvasive pulse oximeter is the simplest way to measure the oxygenation of blood. Arterial blood gases (ABGs) are drawn to measure how much oxygen is in your blood. This helps determine what factors might be contributing to blue fingernails.

Treatment involves the ability to identify the underlying cause and correctly restore adequate oxygen to the blood.

When to call 911

Call 911 if your blue fingernails are accompanied by:

  • shortness of breath, breathing difficulties, or gasping for air
  • chest pain
  • profuse sweating
  • dizziness or fainting
Medically reviewed by Nancy L. Moyer, MD on March 29, 2018Written by J. C. Jones, MA, RN

28 possible conditions

This feature is for informational purposes only and should not be used to diagnose. Please consult a healthcare professional if you have health concerns.

Medically reviewed by Nancy L. Moyer, MD on March 29, 2018Written by J. C. Jones, MA, RN
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