What Causes Blue Fingernails?

Conditions list medically reviewed by George Krucik, MD, MBA

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

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

The discoloration of the skin could also represent a high level of an abnormal form of hemoglobin in the blood circulating throughout your body. Hemoglobin is the protein responsible for transfer 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:

Diseases of the lungs:

  • COPD (emphysema or chronic bronchitis)
  • Asthma
  • Acute respiratory distress syndrome
  • Pneumonia
  • Pulmonary embolism

Diseases of the heart:

  • Congenital heart disease (abnormal structure of the heart and vessels) in children
  • Eisenmenger’s syndrome (late complication of congenital heart disease)
  • Congestive heart failure

Abnormal blood cells:

  • Methemoglobinemia (pediatric genetic disorder)
  • Carbon monoxide poisoning
  • Polycythemia vera

Abnormal blood vessels:

  • Raynaud phenomenon

Diagnosis and treatment of cyanosis

A non-invasive 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 will help determine what factors might be contributing to blue fingernails. Treatment involves the ability to identify underlying cause and correctly restore adequate oxygen to the blood.

When to call 911

You should call 911 if your blue fingernails are accompanied by:

  • shortness of breath, breathing difficulties, or gasping for air
  • chest pain
  • profuse sweating
  • pain or numbness in the arm, hands, or fingers
  • pallor or blanching of the arm, hands, or fingers
  • dizziness or fainting

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.

Conditions list medically reviewed by George Krucik, MD, MBA