If a person's skin or lipsturn blue, it's usuallycaused bylow blood oxygen levels orpoor circulation. It can be a sign of a serious problem, so it's important to seek medical advice.

When bloodbecomes depleted of oxygen, it changes frombright redto darker in colour, and it's this that makes the skin and lips look blue.

In darker-skinned people, the blue tinge may be easier to spot in the lips, gums and around the eyes.

The medical name for this blue tinge is cyanosis.

Content supplied by the NHS Website

Medically Reviewed by a doctor on 28 Nov 2016