What Is Cyanosis?

Cyanosis occurs when there isn't enough oxygen in your blood

Doctor. Christopher Furlong / Staff / Getty Images

The medical term cyanosis refers to when your skin turns blue or purplish in color, almost always because your blood isn't carrying enough oxygen. "Cyan" originates from the Greek word kyanos, which means "dark blue."

Your skin normally has a pink or red tinge to it, regardless of your underlying skin tone. When your body is getting enough oxygen through your lungs and into your bloodstream, this prevailing red tone reflects the oxygen-carrying blood, which is red.

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

It's normal for your veins to reflect this bluish color, since veins deliver blood — with its carbon dioxide 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, it means your muscles, organs and other tissues may not be getting the oxygen they need to operate properly.

Causes of Cyanosis

Cyanosis can be caused by a wide variety of medical conditions, including but not limited to:

  • 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
  • Seizures
  • Drug overdose
  • Suffocation

Most Common Places That Cyanosis May Appear

Mild cyanosis may be difficult to detect even in light-skinned people. In fact, you might not notice the blue tinge on your skin 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 90%.

In people with dark skin, you might not notice cyanosis on the skin, but you may 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 acquire that purplish tinge.

When to Contact a Health Care Professional

Cyanosis may be a sign of a serious medical condition. If you are an adult and have cyanosis, call your doctor or 911 if you experience any of the following:

  • Chest pain (automatic 911 call)
  • 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 mucus


U.S. National Library of Medicine. Cyanosis fact sheet. Accessed Feb. 4, 2016.

Continue Reading