Cyanosis: Symptoms, Causes, Types, Diagnosis, and Treatment — A Complete Guide
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 17, 2026
Quick Answer
Cyanosis is bluish skin, lips or nails caused by a lack of oxygen in the blood [1]. Peripheral cyanosis affects only the hands and feet and is rarely life-threatening [1], while central cyanosis affecting the lips, chest and tongue may signal a serious heart, lung or blood condition requiring immediate treatment [1]. Oxygen therapy is usually first while tests find the cause [1].
What the research says
Pulse oximetry can overestimate oxygen levels in people with darker skin. A systematic review of 44 studies (at least 222,644 participants and 733,722 paired readings) found that most studies reported pulse oximeters overestimating true arterial oxygen saturation in participants with darker skin tones. Risk of bias was high in 64% of studies, the clinical relevance remains unclear, and the bias is likely larger when oxygen levels are lower, so symptoms should be weighed alongside readings (PubMed: Martin et al., Br J Anaesth, 2024 [2]).
Pulse oximetry is very specific for critical heart defects in newborns, though it misses some. A meta-analysis of 13 studies covering 229,421 asymptomatic newborns found a sensitivity of 76.5% (95% CI 67.7–83.5) and a specificity of 99.9% (99.7–99.9), with a false-positive rate of 0.14%. Testing after 24 hours of age had fewer false alarms than earlier testing (0.05% versus 0.50%) (PubMed: Thangaratinam et al., Lancet, 2012 [3]).
Blue lips can come from blood conditions, not just heart and lung disease. A review and case report described a woman with severe headache, cyanosis of the lips and hands, nausea, and breathlessness from methemoglobinemia (blood that cannot carry oxygen properly) whose symptoms resolved after methylene blue. The picture was easily mistaken for a migraine with anxiety. This is a single case plus a narrative review, so it shows the possibility rather than how often it happens (PubMed: Khan et al., Headache, 2020 [4]).
What Is Cyanosis?
Cyanosis is the medical term for when your skin, lips, or nails turn blue due to a lack of oxygen in your blood [1]. The word itself comes from "cyan," a blue-green color [1].
Normally, red blood cells carry oxygen to the tissues throughout your body. Oxygen-filled blood is bright red, which gives skin its pink or red tone [1]. When there is not enough oxygen circulating in the blood, it turns darker with more of a blue or purple tone [1] — and that is what shows through the skin.
If you have darker skin, cyanosis may be easier to see in your lips, gums, nails, and around your eyes [1], and the discoloration may appear more gray or white rather than blue [1].
Cyanosis at a Glance
Key Fact | Detail |
What it is | Bluish discoloration of skin, lips, or nails from low oxygen in the blood [1] |
Root mechanism | Deoxygenated blood is darker blue/purple instead of bright red [1] |
Three types | Circumoral (perioral), peripheral, central [1] |
Common harmless trigger | Cold exposure making blood vessels shrink [1] |
Serious causes | Heart defects, heart failure, pulmonary embolism, COPD, pneumonia [1] |
First treatment | Oxygen therapy while the cause is diagnosed [1] |
Emergency warning | Blue skin plus trouble breathing, chest pain, or confusion — call 911 [1] |
What Does Cyanosis Signify?
Cyanosis can mean your organs, muscles, and tissues are not getting the amount of blood they need to function properly [1]. Many different conditions can cause it. While blue skin and lips are not always a cause for concern, some underlying conditions need immediate medical treatment [1]. Conditions causing cyanosis may be related to your lungs, heart, or central nervous system [1]. The area of your body most affected by cyanosis can help determine the cause [1], which is why doctors pay close attention to exactly where the blue color appears.
The Three Types of Cyanosis
Type | Where It Appears | Typical Causes | How Serious Is It? |
Circumoral (perioral) | Only the mouth or lips [1] | Blood vessels shrinking in cold temperatures [1] | Common and can be normal in newborns [1]; often harmless |
Peripheral | Only hands, fingers, feet, and/or toes [1] | Very cold weather with unprotected hands and feet [1] | Rarely life-threatening, but the cause should be found to prevent permanent injury [1] |
Central | Lips and other areas — chest, cheeks, tongue, gums — in addition to hands and feet [1] | Serious heart, lung, or blood conditions [1] | Potentially life-threatening; seek treatment immediately [1] |
Circumoral cyanosis happens when only your mouth or lips turn blue. It often occurs when blood vessels shrink in response to cold temperatures [1]. It is common — and can be normal — in newborns [1]. In older children, it may appear when they go outside in cold weather [1].
Peripheral cyanosis happens when only your hands, fingers, feet, and/or toes turn blue. This can happen in very cold weather if your hands and feet are not well protected [1]. It is rarely life-threatening, but it is important to find out the cause because it may need quick treatment to prevent permanent injury [1].
Central cyanosis happens when other parts of your body are affected in addition to your hands and feet. This may include your chest, cheeks, tongue, gums, and lips [1]. Serious heart, lung, or blood conditions may be the cause [1]. It is very important to seek treatment immediately [1].
What are the symptoms of cyanosis?
The main symptom of cyanosis is a bluish discoloration of your skin. The bluish tone may also affect your lips, tongue, gums, ears, and nails [1]. If you have darker skin, cyanosis may look more gray or white [1]. It may also show up more around your lips, tongue, gums, nails, and eyes [1].
Cyanosis is typically caused by another condition [1]. Depending on what is causing it, other symptoms you may experience include:
What Causes Cyanosis?
Cyanosis is usually caused by a lack of oxygen in your blood [1]. This may be because your blood does not have enough oxygen in it, or because blood vessels are exposed to cold temperatures [1]. Circulating blood keeps your organs and body parts warm. But if it is very cold out, the blood vessels in your hands, feet, and ears clamp down to keep your body temperature normal [1]. Many conditions can cause your blood to lack the oxygen it needs.
Airway Problems
Lung Problems
Lung Cause | What Happens |
High altitudes [1] | Thinner air contains less oxygen |
Asthma [1] | Narrowed airways reduce airflow |
Respiratory tract infection [1] | Inflammation and fluid interfere with oxygen exchange |
Pulmonary embolism | A blood clot blocks an artery of the lung [1] |
Chronic obstructive pulmonary disease (COPD) [1] | Long-term damage limits oxygen intake |
Pulmonary hypertension [1] | High blood pressure in the lung arteries |
Pneumonia [1] | Infection fills air sacs with fluid |
Heart Problems
Other Causes
Other Cause | What Happens |
Tight clothing | Clothes that limit circulation [1] |
Extreme cold exposure | Blood vessels clamp down in the cold [1] |
Raynaud's phenomenon | A disorder that causes blood vessels to narrow [1] |
Medications | Certain high blood pressure medications [1] |
Seizures [1] | Can disrupt normal breathing |
Drug overdose [1] | Depresses breathing |
Toxic exposures [1] | Chemicals interfere with oxygen transport |
How is cyanosis diagnosed and what tests are used?
Cyanosis is diagnosed by finding its cause, starting with a physical exam and questions about your symptoms, followed by blood, lung and heart tests [1].
How Is Cyanosis Diagnosed?
Cyanosis is a symptom, and your healthcare provider will want to determine the cause of it. They will begin by performing a physical examination and asking you about your symptoms [1]. Questions they may ask include:
Diagnostic Question | Why It Matters |
When did you first notice the cyanosis? [1] | Establishes the timeline |
Did it appear suddenly or come on slowly? [1] | Sudden onset often signals an emergency |
What part(s) of your body are blue? [1] | Determines the type — circumoral, peripheral, or central |
Have you recently traveled anywhere? [1] | High altitudes can cause it |
Are you having trouble breathing? [1] | Points to lung or heart causes |
Are your arms or legs swelling? [1] | May indicate heart failure |
What other symptoms do you have? [1] | Helps narrow the underlying condition |
What Tests Will Be Done?
Your healthcare provider may order tests to determine the cause of the cyanosis. These tests can include various blood, lung, and heart tests [1]:
Test | What It Measures |
Pulse oximetry | A sensor on your finger measures the amount of oxygen in your blood [1] |
Arterial blood gas analysis | Measures oxygen and other substances in your arteries, the blood with the most oxygen [1] |
Chest X-ray [1] | Images the lungs and heart |
Chest CT scan [1] | Detailed imaging of the chest |
Complete blood count (CBC) [1] | Checks your blood cells |
Electrocardiogram (EKG) | Measures your heart's electrical activity [1] |
Echocardiogram | An ultrasound of the heart showing its function and structure [1] |
Pulmonary function tests | Further helps diagnose lung conditions [1] |
Cardiac catheterization | Further helps diagnose heart conditions [1] |
How is cyanosis managed and treated?
Cyanosis treatment depends on its cause, and one of the first treatments a provider may use is oxygen therapy to boost oxygen levels quickly [1].
How Is Cyanosis Treated?
Because cyanosis can be a symptom of many different conditions, the cause of your cyanosis will determine the treatment [1]. One of the first treatments your healthcare provider may use is oxygen therapy. Oxygen therapy provides you with extra oxygen to help boost your levels quickly [1]. You may need a breathing machine or ventilator depending on the severity of your condition [1]. Other possible treatments include:
Treatment | Used For |
Oxygen therapy | The usual first treatment to boost blood oxygen quickly [1] |
Warmth and massage | Cold exposure and conditions such as Raynaud's phenomenon [1] |
Antibiotics | Infections such as pneumonia [1] |
Other medications | Heart and lung conditions [1] |
Discontinuing medication | Medications that restrict blood flow [1] |
Inhalers | Lung conditions such as asthma or COPD [1] |
Surgery | Congenital heart defects such as tetralogy of Fallot, sometimes soon after birth [1] |
How Can I Take Care of Myself?
If cold temperatures or a condition such as Raynaud's phenomenon caused your cyanosis, you may have to make lifestyle changes. You should dress in warm clothes when you plan to be outside. When you are inside, make sure you are in a heated room [1]. It is important that you keep your body warm [1].
You should quit smoking and cut back on your caffeine intake. Caffeine and nicotine can cause your blood vessels to narrow, which can lead to cyanosis [1].
What is the outlook for cyanosis?
The outlook for cyanosis depends on its cause and how quickly you receive treatment, and it is generally not life-threatening [1].
What Can I Expect If I Have Cyanosis?
The outlook for cyanosis depends on the reason for the condition and how quickly you receive treatment [1]. It is generally not life-threatening, but see your provider if you have any other associated symptoms or if the cyanosis happens when you are warm and at rest [1].
Scenario | Typical Outlook |
Cold exposure or Raynaud's | Generally benign; lifestyle changes usually suffice |
Infection (e.g., pneumonia) | Usually improves with antibiotics and oxygen |
Central cyanosis from heart or lung disease | Depends on the underlying condition and treatment speed — seek care immediately |
Newborn circumoral cyanosis | Often normal and resolves on its own |
Can cyanosis be prevented?
Not all causes of cyanosis can be prevented, but some steps can reduce your risk. But there are some things you can do to reduce your risk. Your healthcare provider may recommend you stop taking any medications that restrict your blood flow [1]. You should also quit smoking and limit your caffeine intake [1]. Make sure you dress warmly if you go into cold temperatures, especially taking care of your ears, fingers, toes, and nose [1].
When Should I Seek Care?
Cyanosis needs emergency care if bluish skin comes with symptoms such as difficulty breathing, chest pain, confusion or fever, or appears while warm and at rest. Some are more serious than others. If you have any of the following symptoms along with bluish skin, go to your nearest emergency room or call 911 [1]:
Difficulty breathing
Chest pain
Frequent headaches
Extreme tiredness (fatigue)
Confusion
Fever
Excessive sweating (hyperhidrosis)
Coughing up blood or dark mucus
Pain or numbness in hands, fingers, or arms
Cyanosis that appears while warm and at rest
Conclusion
Cyanosis is your body's visible signal that something is affecting oxygen delivery to your tissues — most often harmless cold exposure, but sometimes a serious heart, lung, or blood condition [1]. The three types (circumoral, peripheral, and central) tell you and your doctor how urgently to act: blue lips alone in a newborn or in the cold may be normal, but blue lips plus your chest, cheeks, or tongue demand immediate medical attention [1].
If you notice unexplained bluish skin, lips, or nails — especially with trouble breathing, chest pain, or confusion — do not wait. Seek emergency care right away. If the blueness is mild and linked to cold, keep your body warm, quit smoking, and limit caffeine, and mention it at your next doctor's visit.
Talk to a healthcare provider about any unexplained bluish discoloration of your skin, lips, or nails — a quick check can tell you whether it is a harmless response to cold or a sign of something that needs treatment now.
Related guides: pulmonary embolism, pneumonia, heart failure, and tetralogy of Fallot.
Frequently Asked Questions
1. What is cyanosis?
Cyanosis is the medical term for when your skin, lips, or nails turn blue due to a lack of oxygen in your blood. The word comes from "cyan," a blue-green color. Deoxygenated blood is darker blue or purple instead of bright red, and that tone shows through the skin. In people with darker skin, cyanosis may look gray or white and is often easiest to see in the lips, gums, nails, and around the eyes.
2. What does cyanosis look like?
Depending on the type, your skin, lips, tongue, gums, eyes, or nails may look different shades of blue or purple. If you have darker skin, cyanosis may look white or gray. Circumoral cyanosis affects only the mouth and lips, peripheral cyanosis affects only the hands, fingers, feet, and toes, and central cyanosis also involves the chest, cheeks, tongue, gums, and lips.
3. What are the three types of cyanosis?
The three types are circumoral (perioral), peripheral, and central. Circumoral cyanosis is when only the mouth or lips turn blue, often from cold, and can be normal in newborns. Peripheral cyanosis affects only the hands, fingers, feet, and/or toes. Central cyanosis affects the lips plus other areas such as the chest, cheeks, tongue, and gums, and may signal a serious heart, lung, or blood condition.
4. Is cyanosis dangerous?
Blue skin and lips are not always a cause for concern — cold-related circumoral and peripheral cyanosis are common and often harmless. However, central cyanosis may be caused by serious heart, lung, or blood conditions and is very important to treat immediately. The outlook depends on the underlying cause and how quickly you receive treatment.
5. What causes cyanosis?
Cyanosis is usually caused by a lack of oxygen in the blood, either because the blood does not carry enough oxygen or because blood vessels are exposed to cold and clamp down. Causes include airway problems (choking, croup, epiglottitis), lung problems (high altitudes, asthma, respiratory infections, pulmonary embolism, COPD, pulmonary hypertension, pneumonia), heart problems (congenital heart defects, congestive heart failure, cardiac arrest), and other factors like tight clothing, Raynaud's phenomenon, certain medications, seizures, drug overdose, and toxic exposures.
6. What other symptoms come with cyanosis?
Because cyanosis is typically caused by another condition, you may also experience low body temperature (hypothermia), numbness or tingling in the arms and legs, coughing, wheezing, difficulty breathing, dizziness, extreme tiredness (fatigue), and weakness.
7. When is cyanosis an emergency?
If bluish skin comes with difficulty breathing, chest pain, frequent headaches, extreme tiredness, confusion, fever, excessive sweating, coughing up blood or dark mucus, or pain or numbness in the hands, fingers, or arms, go to your nearest emergency room or call 911 immediately.
8. How is cyanosis diagnosed?
Your provider will perform a physical examination, ask when the cyanosis started and which body parts are affected, and may order tests including pulse oximetry (a finger sensor measuring blood oxygen), arterial blood gas analysis, chest X-ray, chest CT scan, complete blood count (CBC), EKG, echocardiogram, pulmonary function tests, and cardiac catheterization — all to find the underlying cause, since cyanosis itself is a symptom.
9. How is cyanosis treated?
The cause determines the treatment, and oxygen therapy is usually the first step to boost blood oxygen levels quickly; a breathing machine or ventilator may be needed in severe cases. Other treatments include warmth and massage for cold-related or Raynaud's-related cyanosis, antibiotics for infections such as pneumonia, medications for heart and lung conditions, stopping medications that restrict blood flow, inhalers for asthma or COPD, and surgery for congenital heart defects such as tetralogy of Fallot, sometimes soon after birth.
10. Can cyanosis be prevented?
Not all causes of cyanosis can be prevented, since many underlying heart and lung conditions are not within your control. You can lower your risk by quitting smoking, limiting caffeine, dressing warmly in cold temperatures — especially protecting your ears, fingers, toes, and nose — and asking your provider about stopping medications that restrict blood flow.
11. Is bluish skin normal in newborns?
Circumoral cyanosis, where only the mouth or lips turn blue, is common and can be normal in newborns. In older children, it may appear when they go outside in cold weather. However, any bluish coloring in a newborn should still be evaluated by a healthcare provider to rule out serious causes.
Related Reading
Learn more in our guide to Pulse Oximetry: Normal Oxygen Levels, How It Works and What Affects Accuracy.
References
Cleveland Clinic. Cyanosis. Cleveland Clinic. October 17, 2022. https://my.clevelandclinic.org/health/diseases/24297-cyanosis
Martin D, Johns C, Sorrell L, et al. Effect of skin tone on the accuracy of the estimation of arterial oxygen saturation by pulse oximetry: a systematic review. Br J Anaesth. 2024;132(5):945-956. doi:10.1016/j.bja.2024.01.023. PMID: 38368234.
Thangaratinam S, Brown K, Zamora J, Khan KS, Ewer AK. Pulse oximetry screening for critical congenital heart defects in asymptomatic newborn babies: a systematic review and meta-analysis. Lancet. 2012;379(9835):2459-2464. doi:10.1016/S0140-6736(12)60107-X. PMID: 22554860.
Khan FA, McIntyre C, Khan AM, Maslov A. Headache and methemoglobinemia. Headache. 2020;60(1):291-297. doi:10.1111/head.13696. PMID: 31724752.
Medical Disclaimer
This article is for informational purposes only and does not constitute medical advice. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read here.
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