Coughing up bloody mucus, or sputum, may occur due to a mild respiratory infection, but it may also be a sign of a more severe condition, such as bronchitis. Doctors may refer to it as hemoptysis.

Blood in the sputum is a common event in many mild respiratory conditions, including upper respiratory infections and asthma. However, it can sometimes be a sign of a more serious problem, such as bronchitis or lung cancer. In around half of all people who experience this, doctors cannot identify a reason.

Doctors distinguish between mild and massive hemoptysis. Mild hemoptysis is when sputum has a tinge of blood. This is not usually serious. Massive hemoptysis is when a person produces between 100–1,000 milliliters of blood within 24 hours, which can be life threatening.

In this article, we discuss the causes and treatments of blood in sputum.

A range of factors can lead to blood in the sputum.

The blood usually comes from the lungs, but it can sometimes come from the stomach or digestive tract. If the blood comes from the digestive tract, the medical term is hematemesis.

If the blood is bright red, frothy, and sometimes mixed with mucus, it probably comes from the lungs, as with hemoptysis, and can result from persistent coughing or a lung infection.

If the blood is dark and comes with traces of food, it probably originated in the stomach or elsewhere in the digestive tract, as with hematemesis.

Here are some possible causes of blood in the sputum:

  • Bronchitis involves persistent or recurring inflammation of the airways, a cough, and the production of sputum. It can be chronic or acute, lasting up to 3 weeks.
  • Bronchiectasis describes a permanent enlargement of parts of the airways. It is a long-term condition that can cause shortness of breath and wheezing, as well.
  • A severe or chronic cough can irritate the upper respiratory tract and damage the blood vessels.
  • Inhaling either cocaine or other recreational drugs can irritate and damage the upper respiratory tract.
  • Anticoagulants stop blood from clotting. Examples include warfarin, rivaroxaban, dabigatran, and apixaban.
  • Chronic obstructive pulmonary disease (COPD) obstructs the airflow in the lungs, and usually causes difficulty breathing, a cough, the production of sputum, and wheezing.
  • Pneumonia involves inflammation of the lung tissue, usually because of a bacterial infection. Common symptoms include chest pain when breathing or coughing, fatigue, fever, sweating, and chills. Older adults can also experience confusion.
  • A pulmonary embolism refers to a blood clot in an artery of a lung. It usually causes chest pain and sudden shortness of breath and is a life threatening condition.
  • Pulmonary edema is when fluid is in the lungs. It is most common in people with heart conditions and causes pink and frothy sputum, shortness of breath, and chest pain.
  • Lung cancer is most common in people with a history of smoking tobacco. Symptoms include a cough that does not go away, shortness of breath, chest pain, and sometimes, bone pain or headaches.
  • Neck cancer usually starts in the throat, larynx, or windpipe. It can cause a sore or swelling that does not heal, a permanent sore throat, and a red or white patch in the mouth.
  • Cystic fibrosis is an inherited condition that damages the lungs. It usually causes difficulty breathing and a persistent cough with thick mucus.
  • Granulomatosis with polyangiitis involves inflammation of the blood vessels in the sinuses, lungs, and kidneys. It usually causes a runny nose, nosebleeds, shortness of breath, wheezing, and a fever.
  • Tuberculosis (TB) is a bacterial infection that can lead to a fever, sweating, chest pain, pain while breathing or coughing, and a persistent cough.
  • Mitral valve stenosis involves a narrowing of the heart’s mitral valve. It can cause shortness of breath, swollen feet or legs, heart palpitations, and fatigue, particularly with increased physical activity.
  • A serious injury or trauma to the chest can cause blood to appear in the sputum.

People should seek medical advice if they notice flecks or streaks of blood in their phlegm.

A person needs emergency care when:

To find out why blood is present in the sputum, a doctor will usually take a medical history and perform a physical examination.

During the exam, a doctor may:

  • ask the person to cough
  • check the nose and mouth for bleeding
  • take samples of sputum and blood for testing

In some cases, additional examinations are necessary, including a chest X-ray, CT scan, or bronchoscopy.

During a bronchoscopy, a doctor inserts an instrument called an endoscope into the airway through the nose or mouth. An endoscope has a camera at the end of a tube, allowing a doctor to look for the cause of bleeding and treat it at the same time.

Treatments aim to stop the bleeding and treat the underlying cause.

Depending on an individual’s needs, there is a wide range of options. The approach will depend on the severity of the bleeding and the underlying cause.

Options for treatment may include:

  • a doctor prescribing steroids to manage inflammation, or antibiotics to resolve a bacterial infection, such as TB
  • using tools to stop bleeding or remove a blood clot during a bronchoscopy
  • needing a range of treatment approaches, including chemotherapy and radiation therapy, for people with lung or neck cancer

A person with severe bleeding may need:

  • Bronchial artery embolization: If blood in the sputum results from damage to a bronchial artery, a doctor will recommend a procedure called embolization. A surgeon will pass a catheter into the vessel, identify the source of the bleeding, and use a metal coil, chemical, or fragment of gelatin sponge to seal it.
  • Vasoconstrictors: Drugs, such as vasopressin, can limit bleeding by reducing the size of blood vessels.
  • Blood product transfusion: If clotting problems lead to blood in the sputum, it may be necessary to transfuse elements in the blood, such as plasma, clotting factors, or platelets.
  • Surgery: This may be necessary to remove a damaged or cancerous portion of the airways or digestive system. It is an option when bleeding is severe or persistent.

Severe bleeding in the airways can make it difficult to breathe. In this case, a person may need intubation and supplemental oxygen to help them breathe.

A small amount of blood in the sputum is not usually a cause for concern. In 90% of people with mild hemoptysis, the underlying cause of blood in the phlegm will resolve on its own.

If there is a lot of blood, the outlook may be more serious, as it may be a sign of severe damage to the airways or digestive system. Without treatment, the mortality rate may be as high as 80% because it can affect a person’s ability to breathe. The individual will need immediate medical attention.

In some cases, a person does not produce a lot of blood, but the bleeding is persistent. Bleeding that continues for several weeks may be a sign of lung cancer or another severe illness. People who notice blood in their phlegm often should seek medical advice.

Here are some answers to questions people ask about blood in phlegm.

What does blood in a person’s phlegm mean?

Traces of blood in phlegm can be a sign of respiratory tract infection or a severe cough. If bleeding persists, it may indicate an underlying condition such as TB or bronchiectasis. Massive bleeding can be a sign of severe damage to the lungs or digestive system.

Should a person worry about blood in their phlegm?

In most cases, a little blood in a person’s phlegm is nothing to worry about but it is best to seek advice just to be sure. It may be due to an infection or a cough and usually disappears without intervention.

Persistent bleeding that does not go away may indicate a more serious underlying condition.

If there is a lot of blood, a person should seek urgent medical attention.

Can a cold cause blood in phlegm?

Yes, a long-lasting or severe cough can cause a person to have blood in their phlegm.

Does blood in phlegm always mean pneumonia?

Blood in phlegm does not always mean a person has pneumonia – although it is a common reason why.

In less severe cases, coughing up blood can be the result of a severe cough. In more serious cases, it can point to a chest infection, bronchitis, bronchiectasis, a blood clot, or lung cancer.

It is not uncommon to see traces of blood in phlegm. Often, it results from a respiratory tract infection or other problem that will resolve on its own. However, it is a good idea to speak with a doctor if blood appears in phlegm.

Frequent or persistent bleeding can be a sign of a more serious condition such as lung cancer or tuberculosis (TB), as these will require treatment.

If there is a lot of blood, treat it as a medical emergency and seek urgent medical attention.

Read the article in Spanish.