Blue skin and lips (cyanosis)

Blue skin and lips is usually caused by low blood oxygen levels or poor circulation. It can be a sign of a serious problem. Call 999 or go to your nearest emergency department immediately if you notice an adult or child suddenly turning blue.

When to seek emergency help

Call 999 or go to your nearest emergency department immediately if you notice an adult or child suddenly turning blue.

This is particularly important if they have other symptoms, such as:

  • difficulty breathing
  • chest pain

This could be a sign of a life-threatening problem.

When to see your GP

See your GP if you have cyanosis that:

  • comes on very gradually
  • affects just the fingers, hands, toes or feet

This is usually the result of a less serious problem with blood circulation, but it should still be checked by a doctor.

Common causes of cyanosis

When blood has less oxygen than normal, it changes from bright red to darker in colour, making the skin and lips look blue.  Some of the main causes of cyanosis are described below. You shouldn't use this to diagnose yourself. You should always leave that to your GP.

Cyanosis that just affects the hands, feet or limbs

If just the fingers, toes or limbs have turned blue and feel cold, it's known as peripheral cyanosis.

It can be caused by being exposed to cold air or water. Other causes include poor circulation resulting from:

Cyanosis that affects the skin generally and/or lips

When all the skin and/or lips have a blue tinge, it's known as central cyanosis. It is usually a sign of low levels of oxygen in the blood. Common causes for central cyanosis are listed below.

A problem with the lungs:

A problem with the airways:

A problem with the heart:

Other causes:

The information on this page has been adapted from original content from the NHS website.

For further information see terms and conditions.

This page was published January 2018

This page is due for review December 2020

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