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Coughing up blood

Dr Karen Martin
Reviewed by Dr Karen MartinReviewed on 19.10.2023 | 3 minutes read

Blood in the sputum is also known as hemoptysis. Sputum is usually the mucus substance you cough up from the airways and lungs. Phlegm is the specific term for the mixture of saliva and mucus from your nose, mouth, and throat.

There can be different causes for hemoptysis; some are serious, and some are less so, but you should see your doctor in most circumstances, so they can work out the underlying cause. You may notice a few streaks of blood in the sputum, which commonly come with a chest infection, or clots, or even a pink watery appearance. Still, these indicate an area of tissue damage and warrant a discussion with your doctor.

Doctor’s advice

What causes blood in the sputum?

To work out the cause, it’s worth thinking about the different parts of your breathing system and where the blood could be coming from.

Let’s think about the lungs first. Chest infections are the most likely cause of hemoptysis, especially pneumonia or tuberculosis (TB). Bronchiectasis is a long-term condition that causes the airways to enlarge and produce more mucus and makes getting rid of chest infections more difficult – this may cause a bit of lung trauma that comes up as blood in the sputum. Cancer in the lung can produce hemoptysis, and those who have smoked tobacco or cannabis for years should have a low bar for seeing the doctor if they cough up blood.

A potentially life-threatening cause of hemoptysis, or more specifically, coughing up a pink froth, is a blood clot in the lungs, known as a pulmonary embolism. Certain risk factors exist for this, and you might feel quite unwell.

A problem in the nose might cause nosebleeds and nasal infections, bleeding in the mouth can be caused by certain oral infections and gum disease, and bleeding from the throat can come from vomiting, throat infections, or severe coughing. Cancer can occur in the throat and mouth, and this is more common in those that smoke or chew tobacco or other substances.

Blood-thinning medications like warfarin and aspirin can cause some respiratory system bleeding or exacerbate any of these causes.

The trauma of any part of the respiratory system can cause bleeding, and inhaling a foreign body is one to consider, especially in young children.

When should I worry?

If you are bringing up blood by itself or with minimal sputum, then that is an immediate cause for concern. If you notice blood coming from anywhere else or you are having difficulty breathing, chest pain, weakness, unexplained weight loss, or fatigue, then you should also seek immediate attention. 

If you have been a smoker or ex-smoker for many years or a particularly heavy smoker for a few years and have blood in your sputum, you should see your doctor with urgency. It’s even more important if you have other symptoms like unexplained weight loss, excessive fatigue, or a persistent cough. This is also true for cannabis smokers or smokers of anything else.

If you’ve had a cough lasting more than 3 weeks that you can’t shake, you should see your doctor.

What will my doctor do?

Your doctor will ask about your symptoms and how it started, for example, with a cough or a chest infection, and whether you have any cancer or TB risks.

They will have a listen to your lungs, check your mouth and throat, and assess your breathing rate.

Providing a picture of the sample may be useful, and your doctor may also request a sample of your sputum to send to the lab for testing.

Blood tests can be helpful in deciding if this is an infection or a blood clot. If your symptoms do not improve or they have any other concerns, they may request a chest X-ray.

Further investigation is usually done by a specialist called a pulmonologist, and they will organize a more detailed picture of your lungs called a CT scan. They may also put a tube with a camera (bronchoscope) into your airways to look for abnormalities and take some samples.

How is it treated?

Treatment depends very much on the cause – this is a symptom of an underlying problem. If your doctor suspects an infection, they will treat you with a course of antibiotics. If you are coughing up blood due to coughing repeatedly and severely, you should speak with your doctor before trying any cough suppressants to ensure there is nothing more concerning going on. 

If cancer is suspected, then depending on the location, a combination of surgery, chemotherapy, or radiotherapy will be offered.

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This article has been written by UK-based doctors and pharmacists, so some advice may not apply to US users and some suggested treatments may not be available. For more information, please see our T&Cs.
Dr Karen Martin
Reviewed by Dr Karen Martin
Reviewed on 19.10.2023
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