Blue lips or skin

If a person's skin or lips turn blue, it's usually a sign of low blood oxygen levels or poor circulation.

When blood becomes depleted of oxygen, it changes from bright red to darker in colour, and it is this that makes the skin and lips look blue. 

The medical name for this bluish tinge is cyanosis. In darker-skinned people, cyanosis is easier to spot in the lips, gums and around the eyes.

What to do

Adults

Call 999 or go to your nearest hospital emergency department (A&E) if an adult is turning blue or has blue lips and is showing other warning symptoms, such as difficulty breathing, chest pain, or generally feeling unwell.

If just the fingers, hands, toes or feet are blue, see your GP – the cause is usually a blood circulation problem (see below).

Cyanosis that comes on gradually is usually the result of a long-term heart or lung problem – the person should see their GP as soon as possible.

Children and babies

Call 999 or go to your nearest hospital emergency department (A&E) if a child is turning blue. Trust your instincts and look for these other warning signs:

• breathing difficulty – look out for fast breathing, or breathing with nostrils flared out, or chest muscles pulled in with every breath
• sitting with shoulders hunched
• making a grunting noise
• floppy, tired or not moving around
• no appetite
• irritable

Common causes

You can read on to find the most common causes of cyanosis, but do not use this to diagnose yourself – always leave that to your doctor.

Cyanosis of the hands, feet or limbs

If just the fingers, toes or limbs have turned blue and feel cold, it's known as 'peripheral cyanosis'. The cause is usually poor circulation resulting from either:

• a blockage in the blood supply to or from a limb, such as a blood clot 
• Raynaud's disease, a common condition that affects the blood supply to certain parts of the body, usually the fingers and toes

General cyanosis of the skin and lips

When all the skin and/or lips have a blueish tinge (see picture, top left), it's known as central cyanosis and 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 blood clot in the arteries of the lungs (pulmonary embolism)
• worsening of a long-term lung condition such as chronic obstructive pulmonary disease (COPD) or asthma
• drowning or nearly drowning
• being at a high altitude
• severe pneumonia

A problem with the airways:

• bronchiectasis, where the airways become abnormally widened, leading to a build-up of excess mucus, which makes the airways more vulnerable to infection
• holding breath
• choking – find out what to do if a baby is choking
• croup, a childhood condition (usually viral) affecting the airways, which causes a barking cough
• epiglottitis, inflammation and swelling of the flap of tissue at the back of the throat, usually caused by infection
• seizures that last a long time

A problem with the heart:

• heart failure, where the heart fails to pump enough blood around the body
• a heart defect that was present at birth (congenital heart disease) – cyanosis can happen if the defect allows oxygen-poor blood from the right side of the heart to enter the left side of the heart directly, instead of travelling to the lungs for more oxygen
• cardiac arrest, where the heart stops beating

Other problems:

• a drug overdose (of narcotics, benzodiazepines or sedatives)
• exposure to cold air or water
• a problem with the blood, such as abnormal haemoglobin (the blood cannot take up enough oxygen) or polycythaemia (a high concentration of red blood cells)