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Cyanosis Overview

Cyanosis is the bluish-purple discoloration of the skin due to reduced oxygen concentration in the blood. This bluish hue does not reflect on the whole skin but rather regions where the skin is thin. The appearance of cyanosis can vary in different people. In dark-skinned people, cyanosis can be noticed in lips, gums, eyes, and nails. It can be difficult to detect cyanosis in obese people. Cyanosis is often present with other symptoms, which can signify an underlying disease. 

Types of Cyanosis

Cyanosis is divided into types: Central cyanosis and peripheral cyanosis.

Central cyanosis results due to a reduced amount of oxygen in arterial blood. It can develop when your oxygen saturation level drops below 85%. Central cyanosis is observed on mucous membrane covering gums, inside of cheeks, tongue, sublingual tissue, and tongue.


Peripheral cyanosis occurs when the amount of deoxyhemoglobin increases in the venous blood, especially in regions that supply your peripheries. For this reason, peripheral cyanosis is noticed on the skin from the peripheral areas, such as the hands and feet. 

Causes Of Cyanosis

Central cyanosis can occur due to a problem with blood circulation or ventilation. Acute central cyanosis can result from choking or blockage of the respiratory passage. It can also happen if the intake of oxygen is reduced or compromised. This occurs in case of being stuck in a house fire, carbon monoxide poisoning, hydrogen cyanide poisoning, high altitude, etc. Systemic diseases which can lead to cyanosis include pneumonia, bronchiolitis, asthma, COPD, pulmonary embolism, obstructive sleep apnea, congenital heart disease, valvular heart disease, heart attack, and heart failure. Certain abnormalities associated with hemoglobin can also cause cyanosis.


The causes for peripheral cyanosis are almost similar to that of peripheral cyanosis. But it can also occur if the blood circulation to extremities is blocked or reduced. Cold exposure can cause a bluish tinge in hands and feet due to reduced blood supply. Other causes are hypovolemia, heart failure, Raynaud’s phenomenon, deep vein thrombosis, peripheral vascular disease, etc. 

Cyanosis Risk Factors And Epidemiology

The risk of cyanosis is present in any person who develops a reduced oxygen saturation level or decreased blood supply. If you have a respiratory, cardiovascular, or circulatory condition, the risk of cyanosis is high. Common diseases like heart attack, COPD, obstructive sleep apnea, and asthma can lower the oxygen saturation level in your blood. If you travel to higher altitudes or live in areas with very low temperatures, you may develop peripheral cyanosis due to diminished blood circulation.


Cyanosis can occur in individuals of any age. Congenital cyanotic heart disease is more common among newborn infants. These babies need immediate medical attention for this condition. 

Cyanosis Signs And Symptoms

Cyanosis itself is a sign of reduced oxygen saturation due to external factors or an underlying medical condition. It can occur with other symptoms depending on the type of condition present. If you have a condition that blocks or obstructs your respiratory passage, you may present with other symptoms such as shortness of breath, dizziness, disorientation, wheezing, coughing, weakness, generalized tiredness, etc. Severe symptoms include tachycardia, dyspnea, chest pain, pallor, increased sweating, etc. 

Cyanosis Diagnosis

The diagnosis of cyanosis is made on the basis of history, physical examination, and diagnostic tests. History will include the onset of symptoms, duration, severity, and past medical history. Physical examination is done to observe areas affected by cyanosis. This includes checking your hands, feet, lips, eyes, and inside of your mouth for bluish discoloration. Lab tests that can be done to diagnose a possible cause include CBC, pulse oximetry, arterial blood gases, ECG, echocardiogram, and hemoglobin electrophoresis. Your doctor can also require X-rays or CT scans to visualize the condition of your heart and lungs. 

Differential Diagnosis

Cyanosis occurs due to various causes, so it needs to be differentiated on the basis of history, symptoms, physical examination, and diagnostic tests. Remember that discoloration of the skin due to certain medicines, dyes, birthmarks, or Mongolian spots is different from cyanosis. These skin discolorations are not usually associated with the circulatory or respiratory system. 

Cyanosis Treatment

The treatment for cyanosis depends on its underlying cause. If it occurs due to a freezing temperature or change in altitude, try altering these external factors if possible. Place your hands and feet close to a fire or heating appliance to restore blood circulation. If you have developed any respiratory blockage, it becomes a medical emergency. The first line measures are maintaining a stable airway and improving oxygen supply. This is also known as the ABC of emergency treatment which begins with securing Airway, Breathing, and Circulation. If you have been diagnosed with an underlying medical condition, follow your doctor's guidelines and treatment measures to improve your symptoms. 

Medications are given after the diagnosis of the causative factor. Your doctor can prescribe oral or intravenous medications to reduce cyanotic discoloration and improve oxygen saturation. 


Prognosis depends on the severity of the underlying condition. In the majority of the cases, cyanosis is visibly reduced after treatment. If left untreated, the disease may worsen and cause further complications.


Prevention of cyanosis is associated with preventing causes that may lead to impaired blood circulation or reduced oxygen saturation. Annual tests can guide you about your cardiac and respiratory symptoms, and any abnormalities may get diagnosed earlier. If you have a history of a medical condition that may lead to cyanosis, consult with your doctor to reduce the risk of this condition. 


Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on Nov 09th, 2023.