Question

Reason for blue black colour of nails

Answer 1

Blue fingernails are caused by a low level or lack of oxygen circulating in your red blood cells. This condition is known as cyanosis

Answer 2

What Causes Blue Fingernails?

Medically reviewed by Nancy L. Moyer, MDon March 29, 2018 — Written 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 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.