A little blood when you cough: what to do

Check whether the blood was actually coughed up with phlegm or may have come from your nose, mouth, or gums. If it came from the chest, recurs, or accompanies other symptoms, arrange an assessment without delay.

A dry, forceful cough may break a tiny surface vessel. Acute bronchitis can present with a cough that produces mucus and leaves the airways inflamed. Bronchiectasis can present with frequent productive coughing and intermittent blood. A common cold or allergic rhinitis may cause nasal blood to drain backwards and then appear when you cough or clear your throat.

Asthma commonly presents with wheeze, chest tightness, and cough, but visible blood needs a separate explanation. Acid reflux may present with throat irritation and chronic cough; it does not by itself confirm where blood originated. The pattern and accompanying symptoms matter more than trying to name the condition at home.

Contact a healthcare professional promptly and describe the colour, approximate amount, and whether blood was mixed into mucus. Record recent fever, wheezing, breathlessness, chest discomfort, nasal bleeding, and how long the cough has lasted.

Rest, drink enough fluid to avoid a dry throat, and avoid smoke or vaping. Continue prescribed medicines unless a clinician tells you otherwise. In particular, do not independently stop anticoagulant or antiplatelet medicine; make sure the clinician knows you take it.

Call emergency services for more than a few streaks of blood, bleeding that continues or increases, severe chest pain, marked breathing difficulty, fainting, confusion, or blue-grey lips. Sit upright while help is coming if that makes breathing easier.

Seek same-day care if the blood returns, you develop fever or feel increasingly unwell, or you have an existing lung condition. Prompt evaluation is also sensible if your immune system is weakened or you use medicine that affects blood clotting.

You might ask how the likely source will be checked, whether chest imaging or a sputum test is appropriate, which symptoms to monitor at home, and when a repeat episode should take you directly to emergency care.