Can you elaborate what part of the skin turns blue? Cyanosis is a bluish discoloration of the skin or mucous membranes caused by lack of oxygen in the blood. People whose blood is deficient in oxygen tend to have a bluish discoloration. Usually the oxygen saturation of the blood has to drop below 90% before this occurs.
It is more obvious in the mucous membranes and nail beds, particularly in dark-skinned people. It may also appear on the feet, nose, and ears.
Other causes include: brief exposure to cold air or water, high altitudes, chronic obstructive pulmonary disease (COPD), severe pneumonia, pulmonary edema, congestive heart failure, congenital heart diseases, Shock, aspiration with suffocation, seizures, asthma, crouop, or epiglottitis.
It would be best to have this evaluated further by your doctor for proper diagnosis and management. Take care and regards.