An Overview of Cyanosis

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Cyanosis is when you have blue, grayish, or purple skin because your blood isn't carrying enough oxygen. In some people, the color change may be most noticeable in the nailbeds or lips.

The term originates from the Greek word kyanos, which means dark blue.

Cyanosis means your muscles, organs, and other tissues may not be getting the oxygen they need to operate properly. A variety of things may cause cyanosis, some of which are serious medical concerns.

Close up of red blood cells
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The typical primary symptom of cyanosis is a bluish, grayish, or purplish cast to the skin and/or mucous membranes. A mild case may be difficult to detect even in light-skinned people, so you might not notice the signs until the oxygen content of your blood drops significantly.

Normal blood oxygen saturation is in the range of 95% to 100%, which means almost all of your blood's hemoglobin is carrying oxygen. The bluish tinge to your skin might not appear until your oxygen saturation falls below 85%.

If you have dark skin, you might not notice cyanosis on your skin but may instead see it on the membranes around the lips, gums, and nail beds. These might turn purple instead of blue. The skin around the eyes might also take on that bluish or purplish tinge.

Cyanosis may be a sign of a serious medical condition. If you or a loved one are exhibiting signs of cyanosis, call 911 immediately.

Seek immediate medical help if you experience any of the following:

  • Chest pain
  • Your breathing gets harder or faster and you are unable to take a deep breath
  • You need to lean forward to breathe when sitting
  • You are using the muscles around your ribs, neck, or shoulders to help you breathe
  • You are experiencing frequent headaches
  • You are more sleepy or confused than usual
  • You have a fever
  • You start to cough up dark or blood-tinged mucus


Oxygen is what makes blood red. Getting enough oxygen through your lungs and circulating it effectively throughout your body is what gives your skin a normal pink or red tinge (regardless of your skin tone).

Blood that doesn't have much oxygen in it is carrying mainly waste carbon dioxide from your cells to be exhaled from your lungs. This oxygen-poor blood is darker in color and more bluish-red than true red.

It's normal for your veins to show this bluish color since veins deliver blood—with its waste cargo—back to the heart and lungs to get rid of the carbon dioxide.

But when parts of your body turn blue or purple due to cyanosis, there's an underlying issue that's limiting blood flow or oxygen that must be addressed immediately.

Cyanosis can be caused by a wide variety of medical conditions, such as:

  • Chronic obstructive pulmonary disease (COPD)
  • Pulmonary hypertension (a complication of COPD)
  • Pneumonia
  • Infections of the respiratory tract
  • Asthma
  • Congestive heart failure
  • Raynaud's phenomenon, a condition that causes your blood vessels to narrow, mainly in your fingers and toes
  • Epiglottitis, which is a serious condition involving swelling of the small flap in your throat that covers your windpipe
  • Hypothermia
  • Seizures
  • Drug overdose
  • Suffocation


Cyanosis can be assessed by a physical examination, during which your provider will also listen to your heart and lungs. To confirm a diagnosis of cyanosis, your doctor may order tests or scans such as:


Timely and swift treatment can help prevent any further complications of low blood oxygen.

If you have cyanosis, it's likely that you'll receive oxygen therapy to help boost your blood oxygen levels quickly, but any additional treatment you may receive for cyanosis will depend on the root cause of your condition.

For example, treatment for COPD may include inhaled corticosteroids and pulmonary rehabilitation. Pneumonia treatment may involve antibiotics or antivirals, depending on its cause.

Diuretics and anticoagulants may be recommended to treat pulmonary hypertension.

A Word From Verywell

Cyanosis is a sign of a serious medical condition and requires immediate medical treatment. If you or a loved one are exhibiting any symptoms of cyanosis, such as difficulty breathing and/or a bluish tinge to your skin, nails, mucous membranes, call 911 immediately.

1 Source
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Laskine-Holland ML, Kahr WH, Crawford-Lean L, et al. The association between cyanosis and thromboelastometry (ROTEM) in children with congenital heart defects: A retrospective cohort studyAnesth Analg. 2017;124(1):23-29. doi:10.1213/ANE.0000000000001708

Additional Reading

By Deborah Leader, RN
 Deborah Leader RN, PHN, is a registered nurse and medical writer who focuses on COPD.