The basic nail anatomy consists of the nail plate, nail groove, and the lunula, which is the half-moon-shaped area between the nail plate and eponychium. Blue nails disease, also known as azure lunula, is a condition wherein the lunula takes on a blue color. The nails can sometimes turn blue during exposure to extreme cold, which is easily rectified by warming up. If blue nails are persistent, however, they should not be ignored because that is often a sign of an underlying health problem. Respiratory problems, Wilson's disease, and poor blood circulation are common causes of blue looking nails.
Asthma and emphysema are some of the respiratory diseases that contribute to blue nails because they reduce the amount of oxygen that the body receives. Basically, any chronic obstruction in the airways that deprives the body of oxygen can potentially result in bluish nails. This includes pulmonary edema, which is a fluid buildup, and pulmonary embolism, which is a condition wherein an artery in the lungs becomes blocked by excess fat or a tumor. In some cases, hemoglobin, which is an oxygen-carrying protein, can take on an abnormal shape and also cause the nails to turn blue.
Wilson's disease is also referred to as hepatolenticular degeneration and is often a contributor to blue nails. It is a condition wherein excess amounts of copper build up within the body. The disease also causes changes in the liver and in the basal ganglia, which is the gray matter in the lower parts of the cerebral hemisphere.
Poor circulation is another cause of blue nails. This can be caused simply from being too cold and can be helped by warming up and getting a massage to increase the blood flow throughout the body. Heart problems often affect blood circulation as well and can result in long-lasting discoloration of the nails.
A blue nails diagnosis is important if it is persistent. This is especially true if it is accompanied with other symptoms, such as difficulties with breathing, dizziness, or numbness in the arms, hands, or fingers. It is important to check the nails on a regular basis for any signs of health problems. Keeping the nails well groomed and clean can help in spotting any problems at an early stage. Eating a balanced diet and taking supplements can help to prevent many underlying health conditions and help to prevent many nail diseases as well.