What should you know about cold and coughing up blood?

Small streaks may come from irritated airways after forceful coughing, but blood can also occur with pneumonia, acute airway damage such as bronchiectasis, tuberculosis, or other lung conditions. A pulmonary embolism and lung cancer are less common possibilities that clinicians may need to rule out, depending on your symptoms and risk factors. Blood from the nose, mouth, or gums can sometimes be mistaken for blood from the lungs. Note its colour, amount, frequency, and whether it is mixed with mucus.

Contact a healthcare service promptly, even if the amount seems small or follows a cold. Do not smoke, exercise heavily, or take someone else's medicine while waiting for advice. Keep a record of medicines, especially blood thinners, and describe any recent travel, infection, injury, or procedure. If possible, bring a photo or note describing what you saw, without delaying urgent care.

Call emergency services for more than a trace of blood, repeated bleeding, severe shortness of breath, chest or upper-back pain, fainting, confusion, a very fast heartbeat, or blue lips. Urgent assessment is also needed if you feel suddenly unwell or have one-sided leg swelling with breathing symptoms. Do not drive yourself if you are breathless, faint, or bleeding heavily.

Ask where the blood may be coming from, which examination or imaging may be needed, and whether any medicine should be paused. Tell the clinician about smoking, previous lung disease, tuberculosis exposure, blood-thinning treatment, and changes in your breathing.