Asthma
Blue lips and fingertips: oxygen which is in the air we breathe, is what makes blood have a red color. Blood without oxygen has a blue color. Oxygen enters the body through the air sacs (alveoli) which are at the end of the airways. During an asthma attack it difficult for the body to get enough oxygen because it is difficult to get enough air. As less air with oxygen in it makes it to the air sacs and into the blood, there is less red blood (blood with oxygen in it) and more blue blood (blood without oxygen in it). The blue color of the lips and under the fingernails is because of the blue blood, which can be seen in the small blood vessels under the skin. More parts of the body start turning blue the longer the body goes without oxygen. When parts of the body turn blue because of lack of oxygen it is called cyanosis.