Bluish skin discoloration (cyanosis) may affect your hands, feet, or entire body. Possible causes include heart, lung, and circulatory conditions, some of which are life threatening.
Many conditions can cause your skin to have a bluish tint.
For example, bruises and varicose veins can appear blue. Poor circulation or inadequate oxygen levels in your bloodstream can also cause your skin to turn bluish. This skin discoloration is known as cyanosis.
Cyanosis can affect any part of your body, including your:
- fingers, toes, and nails
- mucous membranes
This bluish coloring is more common in newborns as their skin learns to adjust to the environment, but it can also affect adults. It’s more noticeable on light-colored skin.
Cyanosis is often the result of heart, lung, or circulatory system issues.
Most often, cyanosis is a symptom of a serious health condition. Read on to learn about the types of cyanosis, what causes it, and when you should see a healthcare professional.
There are four types of cyanosis:
- Central cyanosis: In central cyanosis, there’s low overall oxygen available to the body, often due to abnormal blood proteins or a low oxygen state. Central cyanosis may appear all over the body, including the mucous membranes.
- Peripheral cyanosis: In peripheral cyanosis, your limbs aren’t getting enough oxygen or blood flow due to low blood flow or injury.
- Mixed cyanosis: Mixed cyanosis is when peripheral and central cyanosis occur at the same time.
- Acrocyanosis: Acrocyanosis affects your hands and feet when you’re cold, and it should resolve after you warm back up. Primary acrocyanosis results from either a genetic disposition or an unknown cause. Second acrocyanosis has various causes, including low blood oxygen levels, connective tissue diseases, malnutrition, and some inheritable conditions.
The protein hemoglobin appears in the red blood cells and carries oxygen. Cyanosis occurs when hemoglobin is at low levels or doesn’t carry oxygen at all.
Oxygen-rich blood is deep red and causes your skin’s normal color. Under-oxygenated blood is bluer and causes your skin to look a bluish purple.
The normal hemoglobin level is 12.0 to 15.5 grams per deciliter (g/dL) for women and 13.5 to 17.5 g/dL for men, according to the American Red Cross. Cyanosis will become visible when your level of deoxygenated hemoglobin (or hemoglobin without blood) reaches 3.0 to 5.0 g/dL, according to StatPearls.
Cyanosis can develop quickly due to an acute health problem or external factor. It can also be the result of a worsening health condition or develop gradually due to a chronic or long-term health condition.
Many health disorders that involve the heart, lungs, blood, or circulation will cause cyanosis.
Causes of central cyanosis include:
- heart abnormalities that are present during birth and cause blood to bypass the lungs and never collect oxygen
- chronic respiratory diseases, such as asthma or chronic obstructive pulmonary disease (COPD)
- sudden infection in your airways, such as pneumonia
- problems with lung expansion or chest wall injuries
- obstruction of the airway
- pulmonary embolism, which is a blood clot in the lungs
- pulmonary hypertension, which is high blood pressure in the lungs
- obstructive sleep apnea
- hypothermia, or exposure to extreme cold that causes your body temperature to drop
- overdoses of certain medications
- exposure to certain poisons, such as cyanide
Causes of peripheral cyanosis include:
- all possible causes of central cyanosis
- severe anemia, which is a low red blood cell count
- heart attack or heart failure
- severe altitude sickness
- Raynaud’s phenomenon, a condition that can restrict blood flow to your fingers or toes
Most causes of cyanosis are serious and a symptom of your body not getting enough oxygen. Some causes — such as heart attack, heart failure, and those that affect your breathing — are even life threatening.
The term “pseudocyanosis” is used to describe bluish skin that isn’t caused by cyanosis.
Pseudocyanosis may be a side effect of medications, such as:
- amiodarone (Nexterone, Pacerone), which is used to treat atrial fibrillation
- antimalarial drugs, such as chloroquine and hydroxychloroquine
- tetracyclines, a group of antibiotics
The condition methemoglobinemia can also lead to pseudocyanosis. Methemoglobinemia occurs when blood proteins become abnormal and can’t carry oxygen. It’s most often caused by drugs or toxins.
Seek emergency medical attention if you develop cyanosis along with any of the following symptoms:
- difficulty breathing
- shortness of breath
- rapid breathing
- chest pain
- coughing up dark mucus
- extreme fatigue
A doctor can diagnose cyanosis just by looking at your skin. To diagnose the cause of your cyanosis, the doctor will perform a complete physical exam. They’ll ask you about your medical history and when your symptoms developed.
They may also order one or more tests, such as:
- a complete blood count
- pulse oximetry to measure the level of oxygen in your blood
- an arterial blood gas test to measure the levels of oxygen, carbon dioxide, and pH in the blood of your arteries
- an electrocardiogram (EKG) to measure the electrical activity of your heart
- an echocardiogram, which is an ultrasound of the heart
- an X-ray or a CT scan of your chest
- a skin biopsy, in rare instances
The treatment plan the doctor recommends will depend on the underlying cause of your cyanosis.
For example, if you have a condition that affects your airways or breathing, they may prescribe supplemental oxygen therapy. In this therapy, you’ll receive oxygen through a mask or a tube placed in your nose.
For conditions that affect your heart or blood vessels, they may prescribe medications, surgery, or other treatments.
If you’ve received a diagnosis of Raynaud’s phenomenon, the doctor may advise you to dress warmly and limit your time in cold environments. In severe cases, they may prescribe calcium channel blockers, alpha-blockers, or topical medications that help dilate the blood vessels.
Some causes of cyanosis are difficult to prevent. However, taking steps like these can help lower your risk of developing cyanosis and some conditions that cause it:
- Protect your heart, blood vessels, and respiratory system by avoiding smoking and secondhand smoke and exercising regularly.
- Schedule regular checkups with a doctor to monitor your health, and let them know if you notice any changes in your health.
- Follow your doctor’s recommended treatment plan for any health conditions that you have, such as diabetes, heart disease, asthma, COPD, or Raynaud’s phenomenon.
- Wear more layers and warmer clothes during wintertime.
- Get vaccinated to prevent respiratory infections and serious illnesses.