Possible Causes of Blue Fingernails
Low Temperatures
Cold weathers and low temperatures are common reasons why your fingernails may turn blue. When it is cold, the blood vessels in the body are constricted. The smaller pathways make it harder for blood to carry sufficient oxygen-rich blood to the nails. In most cases, this is a normal response of the body to ensure all internal organs stay in the proper temperatures. You may easily deal with this problem by massaging the affected areas or warming them up. Nevertheless, if your fingernails are still blue, it may indicate the presence of a structural abnormality or underlying condition that affect the transportation of oxygenated blood in the body. [4]
