What to Know About Cyanosis in Children

Medically Reviewed by Dan Brennan, MD on February 20, 2024
Written by Sharlene Tan
4 min read

Cyan refers to a shade of blue. Cyanosis, then, is a purple or bluish discoloration of the skin. It’s a sign that there may be low levels of oxygen in the blood. 

Cyanosis is itself a symptom of an underlying medical problem. Your child may have a fever if the cause of cyanosis is infection like pneumonia or croup. Some children may have clubbed fingers if they have congenital heart problems.

There are many different health conditions that may cause cyanosis in children. These are usually problems with their lungs or heart.

Lungs. Problems with your child’s lungs can prevent oxygen from entering their blood. This results in cyanosis. Some lung abnormalities that can lead to cyanosis include:

  • Blockage in the airway that reduces the amount of oxygen getting into their lungs, such as croup or obstruction
  • Lung diseases like pneumonia, bronchiolitis, and asthma
  • Carbon monoxide poisoning or smoke inhalation, which limits the amount of oxygen inhaled

Heart. Cyanotic heart disease is a group of heart defects that are present at birth (congenital heart defects). The most common symptom of a congenital heart defect is bluish or purple skin on the lips, fingers, or toes.

Cyanotic heart disease includes problems with the heart valves like:

Cyanosis can occur when oxygen-poor blue blood doesn’t reach the lungs or when oxygen-rich red blood mixes with blue blood before it returns to the body. Depending on the heart defect, this can be due to different reasons.

For example, for Tetralogy of Fallot, there’s an obstruction that limits the flow of blood to the lungs. This allows the blue blood to be pumped out of the heart to the rest of the body.

Other causes. Other possible causes for bluish skin discoloration include:

  • Birthmarks
  • Eating food that has blue dye in it, like popsicles
  • Some medications may cause grey-blue skin hues. These include silver and amiodarone
  • Blue clothing dye

If the bluish-purple hue is found only on an infant’s feet, hands, and around their lips, this is normal in young children and babies. It’s known as acrocyanosis.

In their first few hours of life, many newborns have acrocyanosis. This is because oxygen and blood is being circulated to more important body parts like their lungs and brain, instead of to their feet and hands.

Children, young adults, and women can also get acrocyanosis, usually after exposure to cold temperatures. It's likely to go away on its own.

If your child has a persistently blue or purple face, tongue, or torso, though, this may be due to a more serious problem. Seek medical help immediately.

Cyanosis is most easily seen where your skin is thin. This includes your:

  • Nose
  • Lips
  • Mouth
  • Earlobes
  • Hands and feet
  • Tips of fingers and toes

In cases of normal blood circulation, oxygen-poor blue blood returns to the right side of your heart. It’s pumped to your lungs, where it picks up oxygen and becomes red. The left side of your heart receives this red blood and pumps it to the rest of your body. Your organs take the oxygen from your blood, and it turns blue again. The cycle begins again as the blue blood returns to your heart.

When red blood flows through the tiny vessels in your skin, it looks red-pink in color. Oxygen-poor blood is blue in color, so it causes your skin to have a bluish-purple hue.

Your doctor will conduct a physical examination and take a medical history. Cyanosis may be harder to spot if your child has a darker complexion. Your doctor may look at your child’s lips, tongue, and nail beds and may compare them to someone with a similar complexion, like a sibling or parent.

Your doctor will also measure your child’s oxygen saturation. This is a painless test that uses a special, lighted device placed on a toe or finger for a few minutes.  This test will determine if the oxygen level is normal or low.

Other tests may be done to find the underlying cause of the cyanosis. These include:

For most children, discoloration is due to acrocyanosis and doesn't need to be treated. It will usually go away on its own.

Some children, though, may need to receive oxygen or a machine to help them breathe. They may also need medication or surgery to treat the underlying condition. When the underlying condition is treated, your child’s skin should return to its normal color.