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Cyanosis - Causes, Symptoms, and Treatment

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Cyanosis - Causes, Symptoms, and Treatment

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Cyanosis is a pathological condition of an underlying disease. This article contains an overview of cyanosis, its types, symptoms, causes, and management.

Written by

Dr. Vidyasri. N

Medically reviewed by

Dr. Mohammad Rajja

Published At July 19, 2022
Reviewed AtApril 1, 2024

What Is Cyanosis?

Cyanosis is bluish hue discoloration of the skin, mucous membrane, gums, and fingernails due to the decreased oxygenation of the blood. The word cyanosis is derived from cyan, representing a bluish-green color. Clinically, cyanosis is evident in cases with oxygen saturation of 85% or less, whereas mild cyanosis can be difficult to diagnose.

What Does Cyanosis Look Like?

The color of the blood appears red because it is fully oxygenated. However, when it lacks oxygen, the blood seems bluish-red or purple. This lack of oxygen supply in the nail bed, skin, or mucous membrane causes the body parts to take up a bluish tint.

What Are the Types of Cyanosis?

Cyanosis is broadly classified into three types:

  • Central Cyanosis: Central cyanosis is manifested by bluish or purple discoloration of the tongue, mucous membrane of the mouth, lips, and skin. It is caused by the desaturation of central arterial blood caused by the diseases of the heart and lungs. Instead of getting carried to the lungs for oxygenation, the deoxygenated blood enters into the general blood circulation of the body, resulting in symptoms of cyanosis.

  • Peripheral Cyanosis: This is characterized by decreased blood circulation in the peripheral organs, limbs, and extremities. This cyanosis is caused mainly due to the stagnation of blood and excessive oxygen intake in peripheral tissues and is not associated with arterial desaturation. There is no bluish discoloration of the mouth seen. The affected areas are changed to bluish or purple in color, and the extremities are usually cold to touch, especially nail beds. Peripheral cyanosis conditions can be resolved with gentle warming.

  • Differential Cyanosis: is characterized by color differentiation involving both the upper and lower extremities. The upper extremities show pink, and the lower extremities are bluish in color. In reversible differential cyanosis, the arms are more cyanotic than the legs. This case is seen in children with transposition of great arteries (TGA), where the oxygenated blood from the pulmonary circulation reaches the descending aorta through the patent ductus arteriosus. Thus the descending aorta is filled with oxygenated blood from the pulmonary circulation resulting in higher oxygen saturation in the lower extremities than upper extremities.

What Causes Cyanosis?

Many underlying health conditions may cause cyanosis. It is usually caused by heart, lungs, nervous system, and blood problems. Central cyanosis causes are classified as:

Causes of Central Cyanosis in Adults:

Causes of Central Cyanosis in Newborns:

  • Pleural Effusion - refers to the build-up of fluid between the tissues that line the lungs and the chest.

  • Respiratory Distress Syndrome - baby’s lungs are not fully developed, which leads to a decreased oxygen supply, causing breathing difficulties.

  • Trachea-Esophageal Fistula - is an abnormal connection between the trachea and esophagus.

  • Pneumothorax - collapsed lung; where the air leaks into the space between the lung and the chest wall. Certain medical procedures, injuries, and lung diseases can result in pneumothorax.

  • Birth Injury or Asphyxia - a condition of deficient oxygen supply due to failure of the respiratory or breathing process.

  • Diaphragmatic Hernia - is a birth defect that refers to a hole in the diaphragm.

  • Blockage in the Upper Respiratory Tract - due to blockage, obstruction may result in decreased blood flow.

  • Transient Tachypnea - newborns with very fast breathing in the first few hours of life.

Causes of Peripheral Cyanosis:

  • Raynaud’s Disease - Areas of the body feel numb and cool due to the constriction of arteries exposed to cold.

  • Hypothermia- A significant drop in body temperature.

  • Heart Failure - The heart fails to pump the blood adequately.

  • Deep Vein Thrombosis - Refers to a blood clot in a deep vein.

  • Hypovolemic Shock- Loss of blood or other fluids makes the heart unable to pump the blood to the body.

What Are the Symptoms of Cyanosis?

Cyanosis may be a symptom of a serious disorder. Symptoms of cyanosis are grouped into central and peripheral cyanosis.

Symptoms of Central Cyanosis:

  • Bluish discoloration of tongue and lips.

  • Squatting in young children.

  • Difficulty or rapid breathing (tachypnea).

Symptoms of Peripheral Cyanosis:

  • The skin appears bluish in color in the toes, fingertips, palms, feet, or other extremities.

  • The affected extremities feel cold to the touch.

  • The color normally regains once the extremities warm up.

  • Low blood pressure.

Other Symptoms of Cyanosis Include:

  • Breathlessness or shallow breathing in pulmonary edema, asthma, and pulmonary emboli cases.

  • Chest pain - in cases of cyanosis due to pulmonary embolism (a condition in which the blockage of lung arteries is caused by a blood clot), edema (swelling caused by excess fluid in the tissues), and pleural effusion (accumulation of fluid between the tissues lining the lungs and the chest).

  • Chest tightness- in case of cyanosis due to pulmonary edema.

  • Fever - in the cyanosis due to pneumonia or pulmonary emboli.

  • Dark mucus or frothy pink sputum is seen particularly in heart failure patients associated with cyanosis.

  • Thickening of the last joint of fingers gives a club-like appearance called clubbing of fingers.

  • Fatigue and headache - in patients with long-term cyanosis.

Symptoms of Cyanosis in Infants:

  • While feeding infants shows symptoms like sweating or feeling tired associated with lack of weight gain.

  • Flaring of nostrils due to labored breathing.

  • Few babies may grunt or emit noise while breathing.

  • Babies are born with low birth weight.

  • Poor feeding or sleeping.

  • Irritability (feeling of frustration or anger).

Symptoms of Cyanosis in Children:

  • Fainting (temporary loss of consciousness).

  • Accommodate a squatting position to relieve breathlessness after physical activity.

  • Repeated chest infections are seen in children with congenital heart disease.

What Are the Possible Complications Caused by Cyanosis?

Cyanosis alarms with the presence of serious life-threatening conditions that are needed to be treated urgently. These includes:

  • Heart Disease: Cyanosis causes congestive heart failure and cardiac arrest.

  • Epiglottis: Swelling of epiglottis (a tissue flap between tongue and windpipe).

  • Gangrene: Dead tissue caused by lack of blood supply or infection.

  • Respiratory Failure: It is a condition where the lungs cannot get enough oxygen into the blood.

  • Sepsis: A life-threatening condition where the body’s response to the infection damages its own tissues.

The failure to treat such emergency conditions results in life-threatening consequences.

How Do Doctors Diagnose Cyanosis?

To rule out the possible cause of cyanosis, proper medical history and thorough examination are carried out through various tests. The heart, lungs, abdomen, chest, hands, and feet are monitored. Various tests carried out include:

  • Blood Oxygen Saturation by Pulse Oximetry:

This test is used to measure the oxygen saturation level of the blood. It is the simplest and most common method to measure how well the oxygen is sent to all the parts of the body. It can detect even small levels of changes in the oxygen levels. A small clip-like device, mostly attached to the finger, and a sensor lights up when the machine is on. In cyanosis, oximeters help to determine the need for supplemental oxygen therapy.

  • Complete Blood Count (CBC):

A blood test is used to evaluate overall health and helps to detect several blood-related disorders. Hemoglobin levels are increased with the presence of chronic cyanosis. In conditions like pneumonia and pulmonary embolism, white cell counts are increased.

  • Chest X-ray:

This test uses radiation to produce pictures of tissues, bones, and organs, including lung, heart, and chest walls. A chest X-ray helps in the diagnosis of congenital heart diseases leading to central cyanosis and other causes of cyanosis such as pneumothorax and pulmonary edema.

  • Electrocardiogram or Echocardiogram (ECG):

This test records the electrical activity of the heart. An ECG helps in the diagnosis of congenital cyanotic heart disease and aids in differentiating the cause of cyanotic heart disease.

  • Chest Computed Tomography (CT):

CT of the chest consists of special X-ray equipment to diagnose abnormalities found with other imaging tests and help to diagnose the causes of chest pain, unexplained cough, fever, and other chest symptoms. This is most effective in diagnosing lung cancer at the earliest stage as it can accurately detect even small nodules in the lungs.

  • Arterial Blood Gas Analysis (ABG):

Arterial blood gas analysis tests help to measure the acidity levels of oxygen and carbon dioxide in the blood. It also measures acid-base (pH) levels.

How to Treat Cyanosis?

Treating cyanosis completely depends on treating the underlying cause. Timely treatment can help to prevent further complications of low blood oxygen.

  • Heat therapy is an application of mild heat to the affected areas that can improve the symptoms of peripheral cyanosis.

  • In children, the inability to feed results in secondary cyanotic heart disease, which leads to metabolic abnormalities such as hypocalcemia and hypoglycemia. Thus metabolic abnormalities need to be corrected.

  • Oxygen therapy is provided initially to reverse the hypoxia condition (low level of oxygen). The goal is to restore oxygenated blood supply as early as possible.

  • Surgical intervention is indicated in babies with congenital heart defects such as Fallot’s tetralogy. Open heart surgery is indicated immediately soon after birth to correct the defects. For less severe defects, surgery is carried out when the baby reaches around three to six months of age.

  • Treatment for peripheral cyanosis relaxes the blood vessels and may include antidepressants, drugs used for treating erectile dysfunction (PDE5 Inhibitors), and antihypertensive medications - ACE inhibitors (angiotensin-converting enzyme inhibitors), and Diuretics (increases the excretion of water through kidneys) are prescribed.

  • In the case of Raynaud’s phenomenon, lifestyle modifications are part of treatment which includes limits or avoiding things that can constrict blood vessels, such as

    • Intake of caffeine and nicotine slowdowns the blood flow and narrows blood vessels. Thus the limited intake of both nicotine and caffeine is beneficial.

    • Certain medications, like decongestants, migraine medications and birth control pills, beta-blockers should be avoided, which further cause constriction of blood vessels and restricts blood flow.

Other lifestyle modifications include exercising regularly, keeping extremities warm, reducing stress, and avoiding rapid temperature changes.


The presence of cyanosis has a lot of clinical significance because of varied differential diagnoses. An interprofessional approach with timely diagnosis and prompt treatment aids in the complete treatment of this condition. It has a better prognosis if treated as early as possible.

Frequently Asked Questions


How to Check Cyanosis in a Patient?

If there is oxygen deficiency in the blood, it will appear dark bluish color, so the skin of the affected person will be bluish in color. Usually, the lips, tongue, feet, hands, and mucous membranes of the oral cavity are the site where discoloration is evident. Clubbing can be seen in a few patients with long-standing central cyanosis.


How to Treat Cyanosis?

The treatment for cyanosis depends on the underlying cause of the problem. Medications will be prescribed to treat underlying heart and lung conditions which may help improve the oxygen supply and blood flow to the organs and tissues. In some cases, oxygen therapy might be required to restore healthy levels.


Does Drug Intake Cause Cyanosis?

Methemoglobinemia is a condition caused due to drugs like antibiotics (Sulphonamides) or antimalarial drugs (Primaquine) or due to genetic abnormalities which can lead to cyanosis. Sulfhemoglobinemia caused due to antibiotics sulfonamides can increase blood cells called polycythemia and may also cause cyanosis.


How Long Does Cyanosis Occur?

Cyanosis may last for 24 to 48 hours. Central cyanosis that occurs due to less arterial oxygen saturation mostly lasts for 5 to 10 minutes in a newborn as the oxygen saturation rises up to 95 percent by 10 minutes of age.


Can Low Blood Pressure Cause Cyanosis?

Reduced blood pressure prevents an adequate supply of oxygenated blood to the extremities. Also, low blood pressure produces reflex cutaneous vasoconstriction that shuts blood from the extremities to the internal organs. This can lead to cyanosis of the extremities.


Can Any Infections Cause Cyanosis?

Yes, cyanosis can be caused by infections like croup (inflammation of the larynx and trachea), septic shock, pneumonia, etc.


Does Anemia Cause Cyanosis?

Cyanosis is more difficult to make out when the level of hemoglobin is low. Approximately 5 g/dL of hemoglobin has to be present in the capillaries to make the dark blue color of cyanosis. For this reason, anemic patients may be hypoxemic without showing any signs of cyanosis.


What Are the Signs of Cyanosis?

Cyanosis occurs when deoxygenated blood, which will appear bluish in color rather than red, circulates through the body. So the skin and mucosa will appear blue in color. Cyanosis can be caused by severe lung or heart disease that causes reduced levels of oxygen in the blood.


Is Cyanosis a Serious Condition?

Cyanosis is a serious condition and occurs when the body does not get enough oxygen. Over a period of time, this condition will become life-threatening, which can lead to heart failure, respiratory failure, and even death if left untreated.


What Is the Type of Cyanosis?

Cyanosis is divided into four different types that include peripheral cyanosis, central cyanosis, differential cyanosis, and cyanosis of babies.


What Is Central Cyanosis?

Central cyanosis is a kind of cyanosis that affects heart or lung disease patients and certain abnormal medical conditions like sulfhemoglobinemia and methemoglobinemia. Bluish discoloration of the tongue and lips is the main symptom seen in patients affected by central cyanosis.


What Is the Difference Between Peripheral Cyanosis and Central Cyanosis?

Central Cyanosis is a condition associated with arterial desaturation and causes bluish discoloration, especially on the mucous membranes of the lips, fingers, tongue, and toes, whereas peripheral cyanosis is not associated with arterial desaturation and causes the fingers and toes discoloration and not the mucous membranes.


What Happens During Cyanosis?

Cyanosis occurs when the oxygen level in the blood is very low. The low oxygen blood is bluish-purple in tint, so the skin turns into bluish color during cyanosis.
Dr. Mohammad Rajja
Dr. Mohammad Rajja

General Practitioner


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