Possible Causes of Blue Lips

An indication your body may not be getting enough oxygen

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Blue lips can occur when blood vessels temporarily shrink after being out in the cold or swimming in chilly water, for example. But they can also be a sign of a medical problem that is causing a reduced amount of oxygen in your blood. This can happen with conditions like asthma, for example, but also medical emergencies like carbon monoxide poisoning.

Cyanosis is the term of when your skin and mucous membranes (like the lining of your mouth) take on a bluish color. In addition to blue lips, you may notice a blue tinge other places, like your nails and earlobes.

This article will go over the medical causes of blue lips and explain when you should seek emergency medical care if your lips turn blue.

Causes of Blue Lips

Brianna Gilmartin / Verywell

Cyanosis Signs and Symptoms

The main sign of cyanosis is a dusky blue or bluish coloring on your lips that looks unnatural. The word cyanosis comes from the word “cyan,” which is a greenish-blue color.

Cyanotic changes like blue lips can come on suddenly or gradually. Usually, the blue discoloration will go away once the cause is found and treated.

Blue lips often occur with blue color changes in other parts of the body. It’s most likely to be seen on parts of the body that have a thin layer of skin with a lot of blood vessels underneath. For example, you might notice a bluish coloration on your:

  • Tongue
  • Gums
  • Nails
  • Earlobes
  • Nose
  • Tips of fingers and toes

Cyanosis might be harder to notice on darker skin tones, which is why it's important to check for it carefully and in various places on the body.

When to Call 911

You should call 911 immediately if your lips turn blue suddenly. You should also seek immediate attention for serious symptoms, such as:

  • Difficulty breathing
  • Chest pain
  • Dizziness or fainting

If your lips turn bluish gradually and you have a known medical condition that could be the cause, call your provider and ask them what steps to take next.

What Causes Blue Lips?

The red blood cells in your body use hemoglobin to carry oxygen to all the tissues. When they dump off oxygen, it changes the configuration of the hemoglobin and makes it a darker color. The blood traveling through the area is as high in oxygen as it normally should be, and this causes blue lips.

Even though this sign is concerning, blue lips do not necessarily mean a part of your body is suffering damage because it's not getting enough oxygen.

For example, an infant born with certain kinds of heart disease might have blue lips and lower-than-normal levels of oxygen in their blood. However, they still can be getting enough oxygen to their body's tissues and no damage is taking place.

In some cases, the body makes up for getting less oxygen—at least temporarily. For example, the body might start making more red blood cells.

On the other hand, it's also possible for your body to not be getting enough oxygen, but you do not have blue lips or other cyanotic symptoms.

Types of Cyanosis

There are two types of cyanosis that typically cause blue lips: central and peripheral. However, blue lips are more likely to occur with the central type than the peripheral type.

  • A bluish discoloration of a lot of your skin as well as your lips is called central cyanosis. It is usually a sign of a medical condition that is preventing your body from getting enough oxygen that needs to be treated right away.
  • Peripheral cyanosis usually just affects your hands and feet. It happens when the blood vessels in these areas get smaller in response to an environmental change like the intense cold.

Rarely, blue lips and other cyanotic characteristics can be caused by exposure to a toxin (such as silver salts) or to certain medications, like amiodarone.

This is called pseudocyanosis and it does not mean there is a problem with the amount of oxygen in the body.

Medical Causes of Blue Lips

In general, blue lips and other cyanotic changes happen because of a medical problem.

Heart Conditions

Heart disease is a major potential cause that must be checked for. In a newborn, blue lips can be a sign of a heart problem they were born with (congenital) that may need a surgical repair. In an adult, blue lips can be a sign of heart failure, a heart valve problem, or another type of heart condition.

Lung Conditions

Serious lung problems are another potential cause of blue lips. Many types of lung conditions can cause blue lips and other cyanotic symptoms, including asthma, pulmonary embolism, chronic obstructive pulmonary disease (COPD), or pneumonia.

Nervous System Conditions

Another cause of blue lips is a serious problem with the central nervous system. If the brain is causing a person to breathe less than normal (hypoventilation), it can cause blue lips.

For example, people may breathe less during a drug overdose, a tonic-clonic seizure, or if there is a major bleed in the brain.

Other Medical Problems

Some other potential causes of blue lips include:

  • Obstructive sleep apnea
  • Being at very high altitudes (acute mountain sickness)
  • Shock
  • Carbon monoxide poisoning
  • Genetic blood disorders (e.g., hemoglobinopathy)

Diagnosing the Cause of Blue Lips

If you have blue lips, you need to see a provider to figure out what's causing it. Even if it's not a life-threatening emergency, you still need to find the cause and treat it as soon as possible.

A provider will ask you about your medical history and current medical problems and symptoms. They will do an exam to look at how your heart, lungs, and other important body systems are working.

They will also look at your body to see if there are other areas of cyanosis, like your tongue, the inside of your mouth, and your hands and feet. They will examine you for changes in the shape of your fingertips (called clubbing), which can mean a long-term problem where there is not enough oxygen being transported in your blood.

Many tests can help your provider determine if your blue lips are an emergency. These tests also can give clues about the possible underlying cause of blue lips:

The timing of blue lips is also important. For example, blue lips present at birth are often from a congenital heart defect. In an adult with a chronic health condition like COPD, blue lips might be a sign that their health condition has gotten worse.

In infants, a usually harmless condition called acrocyanosis can cause a bluish tinge to the arms and legs. Acrocyanosis can sometimes affect the area around the mouth, but blue lips themselves are not usually found. The discoloration is temporary and should go away when the infant is warmed.

Treating Conditions That Cause Blue Lips

The treatment for blue lips depends on the cause. Your provider will first make sure that your airway is clear and that you can breathe and get enough oxygen. You may need to breathe in extra oxygen or need support with a ventilator to help you breathe.

For a problem like congenital heart disease, surgery might be needed. Other causes will need other specific treatments— for example, antibiotics for pneumonia or a diuretic medication for people with heart failure.


Blue lips (cyanosis) can be caused by medical conditions, some of which are serious. Depending on a person’s skin color, it can be hard to spot blue lips which can be a sign that a person’s body is not getting enough oxygen.

If you or someone else gets blue lips and is having trouble breathing or passes out, call 911 or go to the nearest ER. 

4 Sources
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.
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  2. Hiremath G, Kamat D. Diagnostic considerations in infants and children with cyanosis. Pediatr Ann. 2015;44(2):76-80. doi:10.3928/00904481-20150203-12

  3. National Health Service. Blue skin or lips (cyanosis).

  4. MedlinePlus. Blue discoloration of the skin.

By Ruth Jessen Hickman, MD
Ruth Jessen Hickman, MD, is a freelance medical and health writer and published book author.