Synonyms in a broader sense
- Bluish discoloration of the skin
- Blue lips
Cyanosis is a blue or violet discoloration of the skin, usually on the lips or under the fingernails. The violet or bluish color in cyanosis is usually caused by a lack of oxygen in the blood in the affected area. The red blood pigment haemoglobin, which is otherwise responsible for a healthy rosy color of the skin, turns bluish as soon as it no longer binds oxygen.
The reasons for the lack of oxygen in the blood during cyanosis can be many and varied. A rough distinction can be made between a central and a peripheral (i.e. external) cause of cyanosis. Central causes are usually a disease of the heart or lungs.
For example, the loading of the blood with oxygen in the lungs can be disturbed, for example by pulmonary hypertension, or a reduced performance of the heart does not pump enough blood into the body to supply it with sufficient oxygen. A malformation, a “hole” in the heart (ventricular septum defect), which leads to mixing of oxygen-poor blood with oxygen-rich blood, whereby “used” blood is pumped into the body’s circulation a second time, is also possible. In principle, any disorder that impairs breathing can also lead to central cyanosis.
are only a selection of possible causes that affect the lungs. Blue coloration in severe hypothermia can also be counted as central cyanosis. Here the blood vessels in the extremities contract to hold more warm blood in the body core.
Central cyanosis usually affects large parts of the body – lips, tongue and oral mucosa, as well as toes and fingers on all limbs.
- Choking on foreign bodies
- Asthma attacks
- Chronic Obstructive Pulmonary Disease (COPD) after many years of smoking or
- Water in the lungs (edema)
Causes of peripheral cyanosis are mostly occlusions of blood vessels which then disturb the blood flow into the affected body part. Possible causes are blockages of large arteries due to blood clots or mechanical compression (ligature) or a blockage of the finest vessels, the capillaries, as can occur in some autoimmune diseases.
The little blood that continues to enter the area under-perfused with blood does not carry enough oxygen for a correct supply, is “discharged” more quickly and thus causes a blue coloration. Various toxins (chemicals, such as nitrites) can also cause the blood to no longer carry enough oxygen for correct supply, is “discharged” more quickly. However, this does not lead to a typical cyanosis, as the skin takes on a rather grayish color. In addition to the characteristic blue coloration of the skin, people with cyanosis (especially with a central cause) often experience a strong sensation of cold.
