Cyanosis refers to a blue or purple hue to the skin. It is most easily observed on the lips, tongue and fingernails. Cyanosis indicates there may be decreased oxygen in the bloodstream. It may suggest a problem with the lungs, but most often is a result of mixing blue and red blood due to defects of the heart or great vessels. Cyanosis is a finding based on observation, not a laboratory test.
Acrocyanosis refers to the presence of cyanosis in the extremities, particularly the palms of the hands and the soles of the feet. It can also be seen on the skin around the lips. Acrocyanosis is often normal in babies, provided it is not accompanied by central cyanosis.
Central cyanosis refers to the presence of cyanosis on "central" parts of the body, including lips, mouth, head, and torso. Central cyanosis is never normal, and is almost always associated with a decrease in blood oxygen.
Central cyanosis occurs because blood changes color in the presence (or absence) of oxygen. Red blood has ample oxygen whereas blood with decreased oxygen turns blue or purple. Red blood flowing through capillaries in the skin produces a healthy red-pink color. Blue blood causes a blue-purple (or cyan) tint to the skin.
Cyanosis is usually caused by abnormalities of the heart, the lungs, or the blood. Under normal conditions the red (oxygenated) blood delivers oxygen. The returning “blue” (deoxygenated) blood is shipped to the lungs to collect more oxygen.
Abnormalities in the lungs can cause some blood to flow through them without collecting oxygen. Heart abnormalities can cause some blood to bypass the lungs altogether and therefore never collect oxygen. Abnormalities in the blood can decrease its ability to absorb oxygen. The common denominator is that blue blood (deoxygenated) is pumped to the body.
Not all heart or lung disease is associated with cyanosis. The absence of cyanosis may be reassuring, but it does not exclude the possibility of a heart defect.
Parents can usually recognize cyanosis in their children, but it is not always easy (even for physicians). This is especially true in children of darker complexions. The best way to look for cyanosis is to look at the nail beds, lips and tongue, and to compare them to someone with a similar complexion. Usually a parent or sibling serves as a good comparison.
If you think your child has cyanosis, don't panic. Second, examine your child. Cyanosis limited exclusively to the hands, the feet and the area around the lips is known as acrocyanosis and is a normal finding in babies. Cyanosis on the lips, tongue, head or torso is central cyanosis, and should be promptly evaluated by a physician.
If your physician finds that cyanosis is present, they will likely gather more historical information and perform a physical examination. Laboratory evaluation may include blood work or oximetry. Oximetry painlessly "measures" the color of blood (without needles) to determine how much oxygen it contains. The test is performed by placing a special lighted probe on the finger.
Alternatively, your doctor may decide that a consultation with a specialist is in order. Depending on his findings, he may request the services of a heart or lung specialist, the emergency room, or doctors specialized in intensive care.
Treatment depends on the cause.