What should you know about bloody cough?

Blood may come from irritated airways after forceful coughing, acute bronchitis, or an infection. Allergic rhinitis or acid reflux can keep a cough going and inflame the throat, while asthma can cause persistent airway symptoms. Bronchiectasis may produce repeated phlegm and blood because widened airways collect mucus. In children, bronchiolitis can cause breathing difficulty during an infection. The appearance matters: pink-streaked phlegm is different from larger amounts of fresh blood, and blood from the nose or gums can be swallowed and later coughed out.

Contact a clinician promptly, especially if the blood returns or you feel unwell. Keep a note of the colour and amount, whether it is mixed with mucus, how long the cough has lasted, and any fever, chest pain, wheeze, breathlessness, weight change, or night sweats. Do not smoke. Avoid suppressing a productive cough with medicines unless a clinician advises it, and bring a list of medicines, including blood thinners.

Call emergency services for more than a small streak, difficulty breathing, chest pain, a very fast heartbeat, faintness, blue lips, confusion, or bleeding that will not settle. Urgent review is also needed after a chest injury or when coughing blood accompanies severe illness. Children, older adults, pregnant people, and anyone taking anticoagulants should get prompt advice.

Ask whether the blood appears to come from the lungs, throat, nose, or stomach, and whether you need a chest examination, imaging, or a sample of phlegm. Explain your smoking history, recent infections, travel, medicines, and any previous lung condition.