What Is Cyanosis?

Overview

If you find that you have bluish discolouration in your skin, lips, hands, or feet, you may have what is known as ‘cyanosis.’ Cyanosis is a symptom of many diseases or conditions and is not a disease in itself. There are three types of cyanosis: central cyanosis and peripheral cyanosis, which  are the main two types, and there is also differential cyanosis.¹

All types of cyanosis result in bluish discolouration, but the specific area where you might see the bluish skin is what varies between the types of cyanosis. It is usually easier to notice the bluish discolouration in areas where the skin is thin such as your lips, nose, cheek (malar prominences), and ears.¹

Causes of cyanosis

There are several things that may cause cyanosis. However, what the causes have in common is that they essentially result in you not having enough oxygenated blood circulating through your body. Disorders of deoxygenated haemoglobin and disorders of abnormal haemoglobin may cause this.¹

So yes, you aren’t oxygenating well. But why? What medical professionals focus on is looking at why you aren’t oxygenating well. They try to find what is the underlying cause of cyanosis because as discussed earlier, cyanosis is a symptom of something rather than a disease itself.

According to the NHS website, some general causes of cyanosis include:

• Choking
• A blood clot that may reduce blood flow to or from a limb
• Asthma or pneumonia
• Congenital heart disease or heart failure

Common underlying causes of central cyanosis include:^1,2

• Decreased arterial oxygen saturation
• Impaired lung function (obstructive lung disease, pulmonary embolism)
• Impaired gas exchange
• Embolism and ventilation-perfusion mismatch (where even when there is adequate oxygen in the lungs, there isn’t enough blood supply to absorb the oxygen)
• High altitude (decreased atmospheric pressure)
• Right to left shunts in congenital heart disease (cyanotic types, arteriovenous malformations)
• Haemoglobin abnormalities

Peripheral cyanosis is brought about when oxygen extraction in your peripheral tissues increases.¹ Everything that causes central cyanosis can also cause peripheral cyanosis. In addition to this, other conditions that may cause peripheral cyanosis include:^2,3

• Reduced cardiac output following heart failure or shock
• Exposure to low temperatures
• Redistribution of blood flow from extremities
• Arterial or venous obstruction

Signs and symptoms of cyanosis

• Areas of bluish skin in your hands, feet, lips, and tongue (central cyanosis)²
• Areas of bluish skin in your extremities (hands and feet in peripheral cyanosis)²
• In people with darker skin, it may be easier to see the discolouration on the nail beds, lips, and tongue³

Depending on the condition that is causing your cyanosis to occur, other signs, and symptoms you may get include:

• Difficulty in breathing
• Increased rate of breathing
• Secondary polycythaemia (increase in red blood cell count)
• Clubbing is usually observed if the cause is congenital heart disease⁵
• Fatigue
• Coughing
• Hypothermia
• Weakness
• Headache
• Sweating profusely
• Numbness or tingling in the arms, hands, legs, fingers or toes⁶

Management and treatment for cyanosis

Managing cyanosis is centred around finding the underlying cause and treating that particular condition promptly to avoid any secondary problems.³

As well as treating the underlying cause, the treatment of cyanosis often includes oxygen therapy for patients who are hypoxic. Oxygen therapy treatment involves providing you with extra oxygen, which is beneficial as cyanosis is essentially not having enough oxygenated blood circulating in your body.

Doctors may also prescribe you medication to help your blood vessels relax and therefore avoid the vasoconstriction that causes cyanosis (mainly peripheral cyanosis) these include:³

• Antidepressants
• Antihypertensive drugs 

Another course of action your healthcare providers may take, is to take you off certain medications that cause vasoconstriction as a side effect such as birth control pills, beta-blockers, migraine medication.³

It is important to speak to your doctors and get a prescription for these medications or to get advice before stopping other medications.

FAQs

How is cyanosis diagnosed?

As previously mentioned cyanosis is a symptom of an underlying condition or has an underlying cause, therefore healthcare providers will usually focus on determining what that cause is.

They may as ask you questions such as:

• When did you notice the bluish discolouration (if onset is from birth, this may indicate the presence of congenital heart disease)
• Did it come on gradually or suddenly?
• Are you having any breathing problems?

All these questions help guide the medical team to discover the underlying cause of your cyanosis.

Tests and procedures your doctor may take also include tests to assess lung, heart and blood function such as:

• Pulse oximetry
• Arterial blood gas analysis
• Chest x-ray
• Complete blood count: Increased white blood cells (WBC) may indicate conditions like pneumonia and pulmonary embolism. Increased haemoglobin levels are seen in chronic cyanosis
• Electrocardiogram (ECG)
• Pulmonary function tests
• Cardiac catheterisation
• Echocardiogram

How can I prevent cyanosis?

Prevention includes avoiding things that could lead to reduced oxygen saturation or impaired blood circulation.

Some measures that patients can adopt to avoid cyanosis progressing or getting worse based on recommendations include:

• Avoid smoking
• Maintain blood pressure control
• Cholesterol level control
• Avoid extreme cold temperatures
• Avoid being immobile for prolonged periods

Who is at risk of cyanosis?

There are certain factors that increase your chances of getting cyanosis such as:

• Travelling to higher altitudes
• Living in areas with lower temperatures
• People with conditions that may cause them to have reduced oxygen saturation levels or decreased blood supply e.g COPD, obstructive sleep apnoea, asthma⁴

What are the types of cyanosis?

There are 3 types of cyanosis: central cyanosis, peripheral cyanosis and differential cyanosis.^1,3 The 2 main types are central and peripheral cyanosis. The different types of cyanosis differ in cause and therefore the site where the bluish discolouration is seen.

Central cyanosis

Central cyanosis occurs when the level of deoxygenated haemoglobin is 5g/dL and oxygen saturation falls to 85%.¹ The normal range of your oxygen saturation is 95% and above.⁵

Central cyanosis is usually a bigger area of concern because of the element of having reduced arterial oxygen saturation (SaO2) or abnormal haemoglobin. The reduced level of SaO2 is the reason why your central structures and mucosae are affected and get discoloured.²

Diseases of the lung, and heart or abnormal haemoglobin are usually what causes central cyanosis. People with central cyanosis usually also have peripheral cyanosis.

Peripheral cyanosis

People with peripheral cyanosis have normal SaO2 (95% and above) but increased extraction of oxygen in their peripheral tissues. This is due to their peripheral vessels being constricted, therefore reducing the blood flow reaching the periphery tissues.² 

Differential cyanosis

Also referred to as ‘mixed cyanosis’, this type of cyanosis has bluish skin in some areas and not others. For example, you could just have the bluish discolouration in your lower limbs, but not in your upper limbs.³

Pseudocyanosis

This is when your skin has a bluish tint but this discolouration is not caused by lack of oxygen in your body or peripheral vasoconstriction. Pseudocyanosis occurs without an underlying heart or lung problem. It can occur due to contact with metals such as silver or lead or drugs such as chloroquine hydrochloride.⁶ 

How common is cyanosis?

Cyanosis can occur in people of all ages (adults, babies, infants). Cyanosis in babies requires immediate medical attention. So, if you observe bluish discolouration in your baby or infant, the best call of action is to go to the emergency department promptly. 

Congenital cyanotic heart disease, on the other hand, is more commonly seen in newborn babies. 

When should I see a doctor?

If you have bluish discolouration anywhere and warming yourself up doesn’t make it disappear, it's important to seek medical attention in a timely manner. This is especially true if you do not know the cause of your cyanosis or if you see it in young children.

Summary

Cyanosis is the bluish discolouration of your skin due to lack of oxygenated blood in your body. There are various underlying conditions such as congenital heart disease or heart failure that have cyanosis as a symptom. It is best to seek medical attention if you observe this bluish tint on your skin and it does not go away after warming yourself up. 

Treatment of cyanosis is usually centred around treating the underlying condition that is causing cyanosis.