Coughing up mucus with some blood: what to know

Small streaks may come from irritated airways after forceful or repeated coughing, but blood can also occur with pneumonia or bronchiectasis. Less common but serious causes include pulmonary embolism, tuberculosis and lung cancer. The symptom alone cannot identify the cause. A clinician will consider the amount and colour of blood, whether it is mixed through mucus, how suddenly it started, and symptoms such as fever, breathlessness, chest pain or night sweats. Blood from the nose, mouth or gums can sometimes be mistaken for blood coming from the lungs.

Contact a healthcare professional promptly, even if the amount seems small, particularly when the symptom is new or repeats. Note when it happened, how much blood you saw, whether it was bright red or darker, and any medicines that affect bleeding. Do not smoke or vape while waiting for advice. A clinician may listen to your chest and arrange tests such as a chest X-ray, blood tests or other imaging based on the findings. Do not start leftover antibiotics or blood-thinning medicine yourself.

Call emergency services or go to an emergency department if you are coughing up more than a small streak, bleeding is continuing, or you have severe breathlessness, sudden chest pain, a fast heartbeat, fainting, blue lips or confusion. Seek urgent assessment for blood with a recent operation, prolonged immobility, or one-sided leg swelling, because these details can matter when checking for a clot. Do not drive yourself if you feel faint or severely short of breath.

Ask what may be causing the bleeding, which examination or test is appropriate, and how quickly you should receive the result. Tell the clinician about smoking, tuberculosis exposure, previous lung disease, recent travel, surgery, long journeys and medicines that affect clotting or bleeding. Ask which changes mean you should return immediately.