Blood in cough: what it can mean and what to do

Small streaks may appear after forceful coughing, a throat injury, nosebleed drainage or an infection affecting the breathing tubes. Acute bronchitis and a common cold can inflame delicate airway lining. Asthma, bronchiectasis and a cough that continues can also need review. Blood may look bright red, pink or rust-coloured and may be mixed with mucus. A clinician will distinguish blood from the lungs from bleeding in the nose, gums or throat; the appearance alone cannot identify the cause.

Stop smoking or vaping, rest your voice and avoid strenuous activity until you know why it happened. Note when it started, how much you saw, its colour, whether it was mixed with mucus, and whether fever, chest discomfort or breathlessness occurred. Do not take a cough suppressant or blood-thinning medicine specifically for this symptom without professional advice. Arrange a prompt clinical assessment, especially if the bleeding returns or you take anticoagulants.

Seek emergency help for more than a trace of blood, bleeding that does not stop, trouble breathing, chest pain, faintness, confusion, blue lips or a fast deterioration. Urgent assessment is also needed after a chest injury or when blood is accompanied by severe weakness or high fever. Even a small first episode should be discussed promptly if you have lung disease, a weakened immune system or repeated cough.

Ask whether the blood seems to come from the lungs or upper airway, which medicines could contribute, and whether you need an examination or imaging. Share smoking history, recent infections, travel, allergies and any pattern you noticed.