Cyanosis is the medical term for a bluish color of the skin and the mucous membranes due to an insufficient level of oxygen in the blood. For example, the lips and fingernails may show cyanosis. Cyanosis can be evident at birth due to the presence of a heart malformation that permits blood that is not fully oxygenated to enter the arterial circulation. Cyanosis can also appear at any time later in life and often accompanies conditions in which lung function is compromised (resulting in an inability to fully oxygenate the blood) or conditions in which the heart's pumping function is compromised. The presence of abnormal forms of hemoglobin or other abnormalities of the blood cells can also sometimes cause cyanosis. The medical term for lowered oxygen levels is hypoxia; the term anoxia refers to the absence of oxygen.
Pseudocyanosis is the appearance of cyanosis that is not associated with reduced oxygen delivery to tissues. Most causes are related to the ingestion of metals (such as silver or lead) or drugs/toxins.
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.
Pictures, Images, Illustrations & Quizzes
Asthma Attack Signs, Treatments, and Prevention
Look at the anatomy of an asthma attack. See these warning signs and symptoms to avoid an asthma emergency such as a persistent...
COPD (Chronic Obstructive Pulmonary Disease) Quiz
COPD is a combination of three conditions? Take this quiz to learn the three conditions that make up the pulmonary disease called...
Causes of Cyanosis/Turning Blue
Asthma is a condition in which hyperreactive airways constrict and result in symptoms like wheezing, coughing, and shortness of...
There are many unusual symptoms of asthma, including sighing, difficulty sleeping, anxiety, chronic cough, recurrent walking...
Asthma in Children
Asthma in children manifests with symptoms such as coughing and wheezing. Rates of asthma in children are increasing. Asthma in...
Bocavirus infection is usually only found in those with lower respiratory infections or diarrhea. Symptoms include cyanosis,...
Dilated Cardiomyopathy is a condition where the heart's ability to pump blood is decreased because the heart's main pumping...
Hypertrophic cardiomyopathy (HCM) affects many people today. Many people with HCM have no symptoms or only minor symptoms, and...
Restrictive cardiomyopathy, the rarest form of cardiomyopathy, is a condition in which the walls of the lower chambers of the...
Children's Cough Causes and Treatments
Children's cough causes include infection, acid reflux, asthma, allergies or sinus infection, whooping cough, and exposure to...
Congenital Heart Defects
Congenital heart defects are heart problems that are present at birth. Genetics may play a role in some heart defects. Symptoms...
Congestive Heart Failure (CHF) Symptoms, Stages, and Prognosis
Congestive heart failure (CHF) refers to a condition in which the heart loses the ability to function properly. Heart disease,...
COPD (Chronic Obstructive Pulmonary Disease) Symptoms, Causes, Stages, Life Expectancy
COPD or chronic obstructive pulmonary disease is a lung condition caused by smoking tobacco, exposure to secondhand smoke, and/or...
Croup is a contagious viral infection that affects children's respiratory system. Symptoms include a barking cough, stridor,...
Cystic fibrosis is a disease of the mucus and sweat glands. Cystic fibrosis is an inherited disease. The outcome of the disease...
Emphysema is a COPD (chronic obstructive pulmonary disease) that often occurs with other obstructive pulmonary problems and...
Emphysema, Chronic Bronchitis, and Colds
If you have a COPD such as emphysema, avoiding chronic bronchitis and colds is important to avoid a more severe respiratory...
Group B Strep
Group B strep are bacteria called Streptococcus agalactiae that may sometimes cause infections both in a pregnant woman and her...
Heart attack happens when a blood clot completely obstructs a coronary artery supplying blood to the heart muscle. A heart attack...
Heart failure (congestive) is caused by many conditions including coronary artery disease, heart attack, cardiomyopathy, and...
Heart Valve Disease
Heart valve disease occurs when the heart valves do not work the way they should. Symptoms of valve disease include shortness of...
Hyothermia or extreme exposure to cold can be classified as either accidental hypothermia (unintentional cold exposure) and...
Is Respiratory Syncytial Virus (RSV) Contagious?
Respiratory syncytial virus (RSV) is a contagious viral infection that causes symptoms such as decreased appetite, runny nose,...
Is Whooping Cough (Pertussis) Contagious?
Whooping cough (pertussis) is a highly contagious respiratory infection caused by Bordetella pertussis. Pertussis is...
Methemoglobinemia (Beta-Globin Type)
Methemoglobinemia (beta-globin type) is an inherited genetic disorder characterized by an atypical form of hemoglobin that is...
Pneumonia is inflammation of the lungs caused by fungi, bacteria, or viruses. Symptoms and signs include cough, fever, shortness...
Pneumothorax (Symptoms, Causes, Types, and Prognosis)
A pneumothorax is free air in the chest outside the lung, that causes the lung to collapse (collapsed lung). There are two types...
Polycythemia (High Red Blood Cell Count)
Polycythemia (elevated red blood cell count) is a rare blood disease in which the body produces too many red blood cells....
Pulmonary edema (swelling or fluid in the lungs) can either be caused by cardiogenic causes (congestive heart failure, heart...
Pulmonary fibrosis is scarring throughout the lungs. Pulmonary fibrosis can be caused by many conditions including chronic...
Pulmonary Hypertension (Symptoms, Treatment Medications, Life Expectancy)
Pulmonary hypertension is an increase pressure in the pulmonary arteries that carry blood from the lungs to the heart. The most...
Raynaud's phenomenon is characterized by a pale-blue-red sequence of color changes of the digits, most commonly after exposure to...
Epilepsy is a brain disorder in which the person has seizures. There are two kinds of seizures, focal and generalized. There are...
Seizures Symptoms and Types
Seizures are divided into two categories: generalized and partial. Generalized seizures are produced by electrical impulses from...
Ventricular Septal Defect
A ventricular septal defect (VSD) is a congenital heart malformation. A VSD is a hole in the wall of the heart's two lower...
Whooping Cough (Pertussis)
Whooping cough (pertussis) is highly contagious respiratory infection that is caused by the bacteria Bordetella pertussis. There...
Other Causes of Cyanosis/Turning Blue
- Abnormal Hemoglobins
- Cyanide Poisoning
- Diseases of the Heart Valves
- Drug Overdose
- High Altitude
- Hyaline Membrane Disease
- Low Oxygen
- Near Drowning
- Tetralogy of Fallot