Purple or bluish discoloration of the lips could be caused by lack of oxygen in the red blood cells, according to Healthline. Discoloration can also indicate physical defects in red blood cells, such as sickle cell anemia.
The medical term for bluish or purple lip discoloration is lip cyanosis. Lack of blood flow to the lips also results in the purple hue. This can be remedied by warming or massaging the affected area, according to Healthline. An underlying disease may be present if the lips remain blue despite warming. Diseases associated with lack of oxygenated blood supply include asthma, chronic obstructive pulmonary disease, pulmonary edema, aspiration pneumonia or other forms of respiratory illness.
The underlying illness must be addressed in order to restore blood flow to the lips, according to Healthline. Health care professionals use a device called a pulse oximeter to quickly and simply measure the oxygen levels in the blood. Pulse oximetry measures the percentage of oxygen carried by hemoglobin cells. Acceptable percentages of healthy blood oxygenation for adults range from 95 percent to 99 percent, according to Wikipedia. Understanding the percentage of oxygen in the blood stream assists healthcare professionals in determining if oxygen therapy is necessary.