Coughing up blood (haemoptysis): causes, red flags and what happens next

Haemoptysis is blood that comes up from the lungs or airways with a cough. Clinicians first try to establish whether the blood is really coming from the lungs or airways, rather than from the nose, mouth or throat, or from the stomach.

The NHS lists the common causes as a long-lasting or severe cough, a lung or airway infection such as a chest infection, pneumonia, tuberculosis or bronchitis, and bronchiectasis, in which widened airways produce extra mucus. Sometimes it is a sign of something more serious, such as a blood clot or lung cancer. Because the seriousness cannot be judged by looking, the NHS says to get it checked as soon as possible.

The table sets out the causes named by the NHS pages for coughing blood and related conditions.

The NHS gives two levels. For a few small spots, flecks or streaks of blood, or blood noticed in phlegm or on a handkerchief, ask for an urgent GP appointment or get help from NHS 111. Call 999 or go to A&E immediately if you are coughing up more than just a few spots or streaks, or coughing blood and finding it hard to breathe, have a very fast heartbeat, or have pain in your chest or upper back. The NHS says the latter could be a sign of a pulmonary embolism.

The NHS lung cancer page uses a similar approach: urgent GP appointment or 111 if you have coughed up blood or noticed blood on a tissue; 999 or A&E for struggling to breathe, or pain in the chest or upper back. The bronchiectasis page says coughing up more than just a few spots or streaks could be a sign of serious bleeding in the lungs and also lists severe difficulty breathing as a 999 trigger.

The NHS says not to drive yourself to A&E: ask someone to drive or call 999, and bring any medicines you take.

• More than a few spots or streaks of blood, or blood that keeps coming.

• Breathlessness, difficulty speaking, or gasping.

• A very fast heartbeat, light-headedness or collapse.

• Chest or upper back pain.

• A swollen, painful or red calf, which can accompany a clot.

• Blood in phlegm together with weight loss, night sweats or a cough lasting more than 3 weeks.

The NHS lung cancer page says the doctor will ask about symptoms, general health, medical history and any family history of lung cancer, and may listen to the chest. Questions typically cover how much blood, how often, what colour, whether it is mixed with phlegm, any breathlessness, chest pain, fever, weight loss, smoking history, recent travel, contact with TB, leg swelling, long flights or immobility, and medicines such as blood thinners.

Examination may include pulse, blood pressure, breathing rate, oxygen levels, the chest, the legs and the nose and throat.

The NHS says a GP may arrange a blood test or a chest X-ray, and an urgent referral to a specialist if the symptoms could be cancer, which does not definitely mean you have cancer. For bronchiectasis it lists testing a sample of phlegm, a chest X-ray, spirometry and blood tests, with a CT scan to confirm the diagnosis. For tuberculosis, tests include an X-ray, ultrasound, echocardiogram or CT scan of the affected area and taking samples of any mucus you cough up and, if needed, a biopsy.

A suspected pulmonary embolism leads to hospital, where the NHS says you will probably be given an anticoagulant injection before test results; if confirmed, injections continue for at least 5 days, with anticoagulant tablets for at least 3 months. Depending on findings, a CT scan of the chest and a bronchoscopy, in which a thin camera is passed into the airways, may be used to find the bleeding source.

Do not wait to see whether it stops. Note the amount and colour of blood, how often it happens, and any other symptoms, and tell the clinician. If you smoke, say so: the NHS advises not smoking with a chest infection because it can make symptoms worse.

If breathing becomes difficult, sit upright and call 999. Do not drive yourself to hospital; the NHS says to ask someone else to drive or call 999.

Outcome depends on the cause. A chest infection usually settles, with the NHS noting most cases improve in about 7 to 10 days with the cough lasting up to 3 weeks. Pulmonary embolism, the NHS says, usually leads to a full recovery if spotted and treated early. Bronchiectasis cannot usually be cured but can be managed. For lung cancer, the NHS says that if symptoms are caused by cancer, finding it early may mean it is easier to treat.