Medically Reviewed By William C. Lloyd III, MD, FACS

What is cyanosis?

The cyanosis definition is a bluish hue to the skin, gums, fingernails, or mucous membranes due to a lack of oxygen in the blood. When blood is fully oxygenated it appears bright red; when it lacks oxygen supply, the blood is a dark purple or bluish red. This lack of oxygen in the blood supply to a body part, such as the nail bed, skin, or mucous membrane, causes that body part to take on a bluish tint.

There are three classifications of cyanosis:

  • Central cyanosis is a generalized bluish color of the body and mucous membranes.
  • Peripheral cyanosis is a bluish discoloration of the hands, fingertips or toes, and sometimes around the mouth.
  • Differential cyanosis is an uneven bluish discoloration between the upper and lower extremities.

Oxygen is present in your blood and it is bound to the hemoglobin molecule, a red blood cell protein that carries oxygen. As red blood cells travel through the lungs, hemoglobin discards carbon dioxide in exchange for fresh oxygen and becomes bright red. Oxygenated blood flows to cells and tissues in the rest of your body, and releases the oxygen as it captures waste carbon dioxide, at which point the blood turns blue— it becomes cyanotic. Then the blood carrying these deoxygenated red blood cells circulates back again to the lungs for more oxygen.

Cyanosis occurs either when there is insufficient fresh oxygen getting to the bloodstream or when sluggish blood can’t reoxygenate quick enough.

Abnormal hemoglobin or an overall lack of oxygen can cause cyanosis. An overall lack of oxygen may occur due to trauma (like choking or suffocation) or chronic disorders that compromise heart or lung function, such as cyanotic heart disease. Abnormal hemoglobin may, for example, take the form of a disorder called methemoglobinemia. Congenital heart problems can cause cyanosis in babies.

Cyanosis can be a symptom of a serious disorder. Seek immediate medical care (call 911) if you have bluish coloration of the lips or fingernails and experience difficulty breathing, shortness of breath, chest pain, or confusion or loss of consciousness even for a brief moment.

Also seek immediate medical care (call 911) if you are with a child who has bluish skin and is having:

  • Chest muscles pulling in with every breath or flaring nostrils with breathing
  • Fussiness or irritability
  • Grunting
  • Limpness or lethargy
  • Poor feeding or sleeping
  • Sitting very still with shoulders hunched

What other symptoms might occur with cyanosis?

Cyanosis may accompany other symptoms that vary depending on the underlying disease, disorder or condition. Symptoms that frequently affect the circulatory system may also involve other body systems.

Cardiac and respiratory symptoms that may occur along with cyanosis

Cyanosis may accompany other symptoms affecting the heart or respiratory system including:

  • Chest pain
  • Difficulty breathing
  • Leaning forward when sitting to breathe more easily
  • Rapid breathing (tachypnea) or shortness of breath
  • Squatting (young children)
  • Use of rib cage muscles in an attempt to breathe more easily

Other symptoms that may occur along with cyanosis

Cyanosis may accompany symptoms related to other body systems including:

  • Confusion or loss of consciousness for even a brief moment
  • Enlargement of the skin beneath the nail beds (clubbing)
  • Irritability, fussiness, poor feeding, and poor sleeping in infants and young children
  • Lethargy
  • More frequent headaches than you typically have

Serious symptoms that might indicate a life-threatening condition

In some cases, cyanosis may be a symptom of a life-threatening condition that should be immediately evaluated in an emergency setting.

Seek immediate medical care (call 911) if you, or someone you are with, have any of these life-threatening symptoms including:

  • Bluish coloration of the skin, fingernails, or mucous membranes
  • Chest pain or pressure
  • Confusion or loss of consciousness for even a brief moment
  • Difficulty breathing
  • Limpness or lethargy

What causes cyanosis?

Cyanosis causes include abnormal hemoglobin or an overall lack of oxygen. An overall lack of oxygen occurs through trauma, such as choking or suffocation, or such disorders as heart disease and lung disease.

Cardiovascular causes of cyanosis

Cyanosis may be caused by heart and blood vessel disorders including:

  • Blood clot that blocks blood supply
  • Congenital heart defects
  • Methemoglobinemia (overproduction of an abnormal hemoglobin)
  • Raynaud’s phenomenon (spasms of small blood vessels of the fingers and toes, reducing blood circulation; Raynaud’s phenomenon is secondary to many autoimmune disorders, such as lupus)

Respiratory causes of cyanosis

Cyanosis can also be caused by respiratory disorders including:

  • Hyaline membrane disease (respiratory condition common in premature infants)
  • Pulmonary embolism

Other causes of cyanosis

Cyanosis can also be caused by other events or disorders including:

  • Drug overdose
  • Exposure to cold
  • High altitude (decreased oxygen levels)
  • Underwater diving accidents (barotrauma)

Serious or life-threatening causes of cyanosis

Cyanosis may be a symptom of a serious or life-threatening condition that should be immediately evaluated in an emergency setting. These include:

  • Cardiac arrest (cardiopulmonary arrest), which is when the heart and lungs stop working
  • Choking
  • Drug overdose
  • Epiglottitis (life-threatening inflammation and swelling of the epiglottis, a tissue flap between the tongue and windpipe)
  • Near-drowning incident

When should you see a doctor for cyanosis?

Cyanosis can be a symptom of a serious medical condition. Contact your doctor right away for cyanosis that persists or causes concern.

Cyanosis in adults

For adults, call 911 or go to your nearest emergency room for cyanosis when:

  • It is getting harder to breathe or your breathing is getting faster.
  • You cannot catch your breath or get a deep breath.
  • You feel very sleepy or confused.
  • You have chest pain, fever, headaches, or a cough that brings up dark mucus.
  • You need to lean forward to breathe.
  • You need to use the muscles between your ribs to help with breathing.

Cyanosis in babies and young children

For children and infants, call 911 or go to your nearest emergency room for cyanosis along with:

  • Difficulty breathing or breathing faster than 50 to 60 breaths a minute
  • Extreme tiredness, lethargy, limpness, or lack of movement
  • Grunting or hunching over
  • Problems sleeping or lack of appetite
  • Visible movement of the chest or rib muscles or flaring of the nostrils when breathing

How do doctors diagnose the cause of cyanosis?

To diagnose the cause of cyanosis, your doctor will need to take a medical history, perform an exam, and possibly order tests. In emergency situations, it may be necessary to stabilize you first. The exam will concentrate on your heart and lungs. Your doctor will listen to these two organs and may examine your chest, abdomen, neck and hands and feet. You will likely wear a pulse oximeter to measure how well your blood is oxygenated (oxygen saturation).

Questions for diagnosing the cause of cyanosis

Questions your doctor may ask about your cyanosis include:

  • How long have you had this bluish discoloration? What parts of your body are bluish?
  • Are you having difficulty breathing?
  • Do you find it easier to breathe in a specific position?
  • How rapidly did these symptoms come on?
  • Have you inhaled anything?
  • Have you had any swelling, especially in your feet or legs?
  • Do you have any other symptoms?
  • What medications are you taking?

Your doctor may also order testing including:

  • Arterial blood gas analysis, which measures oxygen saturation and other signs of lung function
  • Blood tests, including CBC (complete blood count) and autoimmune tests
  • Chest X-ray or other chest imaging, such as CT (computed tomography)
  • Pulmonary function tests and possibly a bronchoscopy, which uses an endoscope to examine the inside of the lungs and airways

It is not always possible to diagnose an underlying cause or condition. If cyanosis persists and your provider is unable to determine a cause, seeking a second opinion may give you more information and answers.

How do you treat cyanosis?

Since cyanosis is a symptom of a disease or condition, treating it depends on the underlying cause. Often, the first step is to give supplemental oxygen to reverse hypoxia, which is low oxygen levels. Then, doctors can address the root cause. The goal is to restore oxygenated blood supply if possible.

For cyanosis in babies due to congenital heart problems, surgery is often the solution. In other cases, medications are part of the treatment. This includes medicines to treat heart failure or relax the blood vessels. Examples include ACE inhibitors, diuretics, and PDE5 inhibitors. Other causes may also benefit from medication therapy or surgery.

If you have Raynaud’s phenomenon, lifestyle changes are often part of treatment. This includes limiting or avoiding things that can constrict the blood vessels such as:

  • Birth control pills
  • Decongestants
  • Nicotine

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

What are the potential complications of cyanosis?

Because cyanosis can be due to serious diseases, failure to seek treatment can result in serious complications and permanent damage. Once the underlying cause is diagnosed, it is important for you to follow the treatment plan that you and your healthcare professional design specifically for you to reduce the risk of potential complications including:

  • Heart failure
  • Loss of limb
  • Sepsis (life-threatening inflammatory reaction to infection)
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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jun 27
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