Blood in phlegm

NHS Choices information on coughing up blood, including causes such as chest infection, bronchitis, pulmonary embolism, lung cancer and tuberculosis (TB), with links to other useful resources.

Should you be worried?

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If you are having coughing up blood, you need to see a doctor. Please answer these questions to find out how quickly you need to see a doctor. If your child is coughing up blood, then you should see a doctor immediately.


1/11 - Are you having difficulty breathing or are you wheezing?
Yes
No

Coughing up blood can be alarming, but isn't usually a sign of a serious problem if you're young and otherwise healthy . It's more a cause for concern in older people, particularly those who smoke.

The medical term for coughing up blood is haemoptysis.

You may cough up small amounts of bright red blood, or frothy blood-streaked sputum (saliva and phlegm). The blood is usually from your lungs and is often the result of prolonged coughing or a chest infection.

If the blood is dark and contains bits of food or what look like coffee grounds, it may be coming from your digestive system. This is a more serious problem and you should go to hospital straight away. Read more about vomiting blood.

What to do if you cough up blood

See your doctor as soon as possible if you cough up blood. It's particularly important to see your doctor if:

Your doctor will be able to assess whether you may have a serious medical condition that needs to be investigated and treated. Call your local out of hours service if you can't see your doctor.

Call for an ambulance or go to your nearest Emergency Department immediately if you're coughing up significant amounts of blood or are struggling to breathe.

Tests that may be needed

You may be asked for a sample of your sputum so it can be checked for infection. Other tests, such as blood tests , may also be needed.

Your doctor may decide to refer you to a specialist at your local hospital for a chest X-ray or a more detailed scan, such as a computerised tomography (CT) scan .

In some cases, further tests may be required to find out where the blood is coming from. For example, you may be referred to a specialist who may decide to arrange a test called a bronchoscopy (where the main air passages of your lungs are examined using a tube with a camera at one end).

This page can give you a better idea of what the cause may be, but don't use it to diagnose yourself. Always leave that to a doctor.

Common causes of coughing up blood

The most common reasons for coughing up blood are:

  • a prolonged, severe cough
  • a chest infection – this is more likely if your sputum is discoloured or contains pus, you have a fever, or you have a tight feeling in your chest
  • bronchiectasis – this is more likely if you're also wheezy or short of breath

Sometimes a severe nosebleed or bleeding from the mouth or throat can cause blood to come out in your saliva when you cough.

Less common causes of coughing up blood

Less commonly, coughing up blood may be the result of:

  • pulmonary embolism (a blood clot in the lungs) – this usually causes sudden shortness of breath and chest pain
  • pulmonary oedema (fluid in the lungs) – your sputum will be pink and frothy, and this usually occurs in people with pre-existing heart problems
  • lung cancer – this is more likely if you're over 40 and smoke
  • tuberculosis (TB) – a severe lung infection associated with fever and sweating; this is becoming more common in the UK, but can be treated with prolonged antibiotics
  • cancer of the throat or windpipe
  • taking anticoagulants – medications that help stop your blood clotting, such as warfarin , rivaroxaban, or dabigatran

Sometimes, no cause can be found and it never happens again.

Common questions about blood in phlegm

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What does it mean when you cough up blood?

Coughing up blood either on its own or mixed with phlegm is not usually a sign of a serious problem if you are young and have no other health conditions. However, it can be a sign of something serious if you are older or if you smoke.

The most common reasons for coughing up blood are:

Less common causes of coughing up blood can include:

In some people, coughing up blood is a one-off event and no cause is found.

If you are coughing up small amounts of blood, see your doctor as soon as possible.

If you are coughing up a lot of blood or you can’t stop coughing blood, this is a medical emergency. Go to hospital immediately or call an ambulance.

What is haemoptysis?

Haemoptysis is the medical term for coughing up blood.

In most cases, the blood comes from your airways or lungs, usually because of a long-term cough or a chest infection.

Sometimes, the blood can be dark and contain bits of food or what looks like coffee grounds. This suggests that the blood may be coming from your digestive system. If this happens, see a doctor or go to a hospital immediately.

Can an upper respiratory infection cause you to cough up blood?

Yes. An upper respiratory tract infection that causes a prolonged, severe cough can cause you to cough up blood.

If the infection spreads into your chest, it can cause other conditions, such as bronchitis and pneumonia, which can also cause you to cough up blood.

If you are coughing up blood because you have a respiratory infection, the blood is likely to be mixed up with spit or phlegm. You may also have other symptoms, such as fever (high temperature) and cough.

Can you cough up a blood clot?

It is possible to cough up a blood clot. This is a medical emergency that can be a serious side effect of taking anticoagulant medicines.

See your doctor or go to a hospital immediately if you are coughing up blood clots or large amounts of blood.

You should also see your doctor as soon as possible if you are coughing small amounts of blood. They will be able to check the cause and give you any treatment you may need.

Some people can develop a blood clot in their lungs (pulmonary embolism). This can cause them to cough up blood.

Can a nosebleed cause you to cough up blood?

Having a nosebleed does not technically cause you to cough up blood, but it can create the impression that you are coughing up blood. This is because when a person coughs up blood, the blood usually comes from the airways or lungs. However, when you have a nosebleed, the blood can run down, gather in your throat and come out in your saliva when you cough.

Can you cough blood from coughing too much?

Yes. An ongoing severe cough is a common reason for coughing blood.

What should you do if you’re coughing up blood?

There are many reasons why a person may cough up blood. If you are young and otherwise healthy, coughing up blood is not usually a sign of a serious problem. However, it can be a sign of something serious if you are older and smoke.

If you are coughing up lots of blood or it won’t stop, go to a hospital immediately or call an ambulance.

If you are coughing up small amounts of blood, see your doctor as soon as possible. Your doctor can check if you need any investigation or treatment.

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