If you have blue or purple nail beds or fingernails, it may be due to an underlying condition known as cyanosis. This condition is caused by a lack of oxygen in the blood. Cyanosis can result from exposure to cold temperatures, certain lung and heart conditions, circulation problems, issues with hemoglobin, and more.
In addition to fingernails, cyanosis commonly impacts the hands, soles of the feet, and mouth. It can affect people of all ages, including newborns.
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This article looks at the different causes of blue and purple nail beds or nails, as well as other associated symptoms.
What Causes Blue or Purple Nails?
Blue or purple nail beds or nails are a common sign of cyanosis, which is caused by a lack of oxygen in the blood. This type of discoloration can also occur on other parts of the body including the hands, fingertips, toes, nose, lips, and tongue.
Cyanosis is often caused by exposure to cold temperatures. However, it can be caused by an underlying medical condition or other external factors. These include:
- Lung conditions
- Airway obstruction
- Heart conditions
- Other issues
What Are the Different Types of Cyanosis?
There are three types of cyanosis:
- Central: Central cyanosis is blue discoloration that is seen on the tongue, lips, other areas within the mouth, as well as parts of the eye. This type of cyanosis is commonly associated with heart and breathing conditions, as well as drug use.
- Peripheral: This type of cyanosis is seen as blue or purple discoloration in the nails, fingers, toes, and nose. Cold exposure and vasospasms are common causes. It is also associated with the same underlying conditions as central cyanosis.
- Differential: This type of cyanosis is seen as blue discoloration in certain areas of the body, such as the upper or lower body, or right or left side of the body. This type of cyanosis is associated with structural heart issues that are present at birth.
Lung Conditions
Certain lung conditions can cause a lower than typical level of oxygen in your blood. This is also known as hypoxemia. These conditions include:
- Pneumonia, a lung infection
- Bronchiolitis
- Chronic obstructive pulmonary disease (COPD)
- Asthma
- Interstitial lung disease
- Pulmonary hypertension
- Pulmonary embolism, a blood clot in the arteries of the lung
Does COVID-19 Cause Purple Nail Beds?
Severe illness with COVID-19 can lead to breathing problems and cyanosis. According to the Centers for Disease Control and Prevention (CDC), if you experience pale, gray, or blue-colored skin, lips, or nail beds, you should seek immediate medical attention.
Airway Obstruction
Obstruction of the airway can make it difficult or impossible to breathe. This can lead to lower levels of oxygen in the blood and tissues. It can be caused by:
- Obstructive sleep apnea
- Choking on something stuck in the airway
- Swelling or inflammation around the vocal cords (croup) or epiglottis (epiglottitis)
Heart Conditions
Certain cardiac conditions can affect how much oxygenated blood the heart is able to pump throughout the body. If this output is not able to meet the body's needs, it can cause cyanosis and other serious issues. These conditions include:
- Heart failure and shock, or when the heart doesn’t pump enough blood for your body’s needs
- Congenital heart disease, or heart structural issues present from birth. They include: coarctation of the aorta, interrupted aortic arch, patent ductus arteriosus.
- Heart valve disease
- Sudden cardiac arrest, or when the heart stops working
Cyanosis in Newborns
While cyanosis may be commonly seen in newborns, central cyanosis that lasts longer than 10 minutes may be associated with life-threatening conditions and is considered an emergency.
Other Causes of Cyanosis
Other types of health conditions, as well as environmental factors, can cause cyanosis. They include:
- Cold exposure
- Blockage in a vein or artery
- Raynaud's syndrome
- Drug overdose (narcotics, benzodiazepines, sedatives)
- High altitudes (low-oxygen environment)
- Issues with hemoglobin, a substance that carries oxygen in the blood
- Cyanide or carbon monoxide poisoning
- A seizure that lasts a long time
What Causes White Spots on Nails and How to Treat Them
What Are Other Symptoms of Cyanosis?
The place on the body where cyanosis shows up will vary depending on the specific type. The condition triggering cyanosis may also cause other symptoms, including:
- Shortness of breath
- Fatigue
- Cough
- Chest tightness or chest pain
- Loss of appetite
- Stomach pain, nausea, and vomiting
- Finger clubbing (enlargement of the fingertips)
- Weakness
- Ankle, foot, or leg swelling
- Rapid breathing
- Confusion
- Leg pain
- Clammy skin
- Anxiety
- Cold sensitivity
- Numbness or tingling
- Irregular heartbeat
Infants may also have difficulty gaining weight, have feeding problems, and have a decreased appetite.
When to Call a Healthcare Provider
You should call 911 or seek emergency medical care if your cyanosis symptoms are accompanied by:
- Chest pain
- Profuse sweating
- Clammy skin
- Shortness of breath
- Difficulty breathing
- Dizziness or fainting
These could all be signs of a medical emergency like a heart attack or pulmonary embolus, or one or more blood clots in the lungs.
Diagnosing Cyanosis
When diagnosing cyanosis, your healthcare provider will do a physical exam, review your medical history, and run certain tests.
Your healthcare provider will perform a physical exam to determine which type of cyanosis you may have, as well as what the potential underlying condition may be. They will take into consideration the exam room’s temperature, as well as the lighting while conducting this exam.
Your healthcare provider will go over your medical history. Along with other questions, you’ll be asked about when your symptoms began. This will help them determine whether or not this is due to a condition that you’ve had since birth.
Beau’s Lines
Diagnostic Tests
Tests that may be used to diagnose this condition:
- Pulse oximetry: This noninvasive test uses a probe or sensor to estimate the amount of oxygen available in the blood. It may be used to check for central and peripheral cyanosis, as well as for heart structure issues that may indicate differential cyanosis.
- Arterial blood gas analysis (ABG): This blood test shows oxygen and carbon dioxide levels in the blood, as well as the blood’s acidity level. This test also looks at hemoglobin. This may be used to check for central and peripheral cyanosis.
- Computed tomography scan and X-rays: These imaging tests may check for peripheral cyanosis, as well as lung, and heart conditions.
- Echocardiogram: This test uses sound waves to take pictures of your heart. This checks for structural issues and heart functioning.
Other tests may be performed based on your results.
A pulse oximetry needs to be done with an ABG test since it can have a false-positive reading in people with peripheral cyanosis.
Differential Diagnosis
During the diagnostic process, your healthcare provider will rule out a condition called pseudocyanosis. This is not true cyanosis, even though it presents in a similar way. Ingesting metals like iron, as well as some medications, may cause this.
Summary
If you have blue discoloration on your nails, or other areas of your body, you may have cyanosis. This is caused by a lack of oxygen in the blood.
There are three different types of cyanosis and each leads to blue discoloration in different areas of the body. The underlying condition causing cyanosis may also lead to symptoms.
The skin discoloration associated with cyanosis might just be a temporary event brought about by cold weather. However, this shouldn’t be brushed aside as an unimportant health concern. Be sure to check in with your healthcare provider even if your symptoms go away quickly.
To diagnose cyanosis, your healthcare provider will review your medical history, do a physical exam, and run specific tests. Cyanosis is highly varied and treatment for it is based on the underlying cause.
Frequently Asked Questions
What does it mean when your fingernails turn blue?
Cyanosis occurs when parts of the body turn a shade of blue or purple. This is due to blood carrying less oxygen. This means bodily structures such as organs might not be receiving enough oxygen.
How does anemia affect fingernails?
Iron deficiency anemia may cause one or more fingernails to have raised ridges, become thin, and curve inward.
Should I be worried if my nails become purpler or blue?
If it is temporary and due to the cold, it may not be something to worry about. However, it’s always best to check in with your healthcare provider to make sure there isn’t an underlying condition causing this symptom.
9 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.
MedlinePlus. Blue discoloration of the skin.
Pahal P, Goyal A. Central and peripheral cyanosis. In: StatPearls [Internet].
Centers for Disease Control and Prevention. Symptoms of COVID-19.
Kataoka H. Proposal for new classification and practical use of diuretics according to their effects on the serum chloride concentration: rationale based on the “chloride theory”. Cardiol Ther. 2020;9(2):227-244. doi:10.1007/s40119-020-00172-9
UpToDate. Overview of cyanosis in the newborn.
National Library of Medicine: MedlinePlus. Cyanotic heart disease.
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By Brian Mastroianni
Mastroianni is a health and science journalist based in New York with a master's degree in journalism.
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