Coughing up blood

Coughing up blood is called haemoptysis. The blood comes from the breathing tubes or lungs and may appear alone or mixed with mucus, also called phlegm or sputum.

A few streaks can happen when coughing irritates a small blood vessel. Chest infections are another common cause. However, the amount or colour does not reliably show the cause, so true coughing up of blood needs prompt medical advice.

Blood from the nose, mouth or gums may also be coughed or spat out. Vomited blood comes from the digestive system. These can look similar, and you do not need to identify the source before seeking help.

The blood may be:

• Thin red streaks in clear, yellow or green phlegm
• Small bright-red spots or clots
• Rust-coloured or blood-stained mucus
• Frothy blood mixed with air and mucus

You may also have a cough, fever, chest discomfort, wheezing or shortness of breath.

Notice roughly how much blood there is, how often it happens and whether it is mixed with phlegm. A photograph may help a clinician, but do not delay care to take one.

Respiratory infections are common causes. Bronchitis can cause frequent coughing that irritates small blood vessels. Pneumonia may produce blood-stained phlegm with fever, tiredness or chest pain.

A forceful or long-lasting cough may damage a small surface blood vessel, usually causing a few streaks. Long-term conditions such as chronic obstructive pulmonary disease, or COPD, and bronchiectasis can cause repeated bleeding.

Sometimes blood comes from a nosebleed, bleeding gums or a mouth injury rather than the lungs.

Less common causes include tuberculosis, fungal infections, inflammatory blood-vessel conditions and certain heart conditions. Medicines that reduce clotting can make bleeding easier or more noticeable.

Lung cancer is possible, particularly when bleeding persists or occurs with unexplained weight loss, ongoing chest pain or a change in a long-term cough. Many people have another cause, but these symptoms need assessment.

A pulmonary embolism, or blood clot in the lung, may cause coughing up blood with sudden breathlessness or pain that worsens when breathing in. This requires emergency care.

Seek same-day medical advice if you cough up any blood that appears to come from your chest, even a few spots or streaks. This is especially important if it happens again, you have a fever, or you have a lung or heart condition.

Call emergency services now if:

• There is more than a few spots or streaks, or bleeding continues
• You are struggling to breathe
• You have chest or upper-back pain, a very fast heartbeat or blue-grey lips
• You feel faint, confused, very weak or unusually drowsy
• Blood appears with sudden breathlessness or one-sided leg swelling

Do not drive yourself if you are seriously unwell. Bring your medicines or a current medication list, especially if you take anticoagulants or antiplatelet medicines.

After urgent assessment, arrange follow-up if your cough continues, the blood returns or recommended tests have not been completed.

A clinician will ask when bleeding began, how much you saw and whether it was mixed with mucus. They may ask about infections, travel, blood-clot risks, smoking, lung conditions and medicines.

Your mouth and nose may be checked for another source. The clinician may also assess your breathing, oxygen level, temperature, pulse and chest.

A chest X-ray is often an early test. Further testing may include:

• Blood tests for infection, anaemia and clotting problems
• A phlegm sample to look for infection
• A CT scan of the lungs and blood vessels
• Bronchoscopy, using a thin camera to examine the breathing tubes

The tests needed depend on the bleeding, other symptoms and initial findings.

Treatment depends on the cause and amount of bleeding. A bacterial infection may need antibiotics like amoxicillin or doxycycline, but antibiotics do not treat viral infections. Long-term airway conditions may require treatment to clear mucus or control inflammation.

Significant or continuing bleeding may require hospital care. Doctors may control it during bronchoscopy or block the bleeding vessel using bronchial artery embolisation.

Until assessed, rest and avoid smoking or vaping. Record further bleeding and related symptoms.

Do not use leftover antibiotics or someone else’s medicine. If you take a prescribed blood thinner like warfarin or apixaban, do not stop it yourself. Seek urgent advice because suddenly stopping it can also be harmful.

A small amount caused by infection or airway irritation may stop as the cough improves. Recovery depends on the underlying cause.

Further review may be needed if bleeding returns, the cough does not settle or a test is abnormal. Repeated episodes should not automatically be assumed to have the same cause.

If the first assessment finds no cause, a clinician may recommend monitoring or additional imaging based on your symptoms and risk factors.

Is blood-streaked phlegm the same as a large lung bleed?

No. A few streaks differ from ongoing or heavy bleeding, but both need assessment. Larger amounts, clots, breathing difficulty or weakness require emergency care.

How can I tell coughing up blood from vomiting blood?

Blood from the airways often follows coughing and may be bright red or frothy. Vomited blood may follow nausea and look dark or like coffee grounds. These clues are not always reliable, so seek urgent help for either.

Can a nosebleed cause blood in phlegm?

Yes. Blood can run down the throat and later be coughed or spat out. A clinician may examine your nose and mouth to identify the source.

Could a blood thinner be responsible?

Blood-thinning medicines can make bleeding easier or harder to stop, but another cause may still be present. Tell the clinician what you take and when you last took it.

Does coughing up blood mean cancer?

Not necessarily. Infections and irritated airways are common causes. Cancer is possible, so persistent or repeated bleeding should be investigated.