Cough with a small amount of blood: what to know

A hard bout of coughing can irritate small blood vessels in the throat or airways. A common cold or acute bronchitis may produce inflamed mucus, while bronchiectasis can cause recurring phlegm and bleeding. Nose or gum bleeding may also mix with saliva. Asthma, allergies and reflux can trigger coughing but do not explain every episode of blood. The source, recurrence and accompanying symptoms help a clinician decide what examination is needed.

Arrange medical advice and keep a note of the colour, amount, timing and whether the blood is mixed with mucus. Mention smoking, recent infection, chest symptoms, recent travel or injury, and any blood-thinning medicine. Rest your voice, avoid smoke and do not take leftover antibiotics. If bleeding recurs, update the clinician rather than waiting for it to disappear again.

Call emergency services if bleeding increases, repeats over a short time, or occurs with breathlessness, chest pain, fainting, confusion, blue lips or severe weakness. Seek prompt assessment for unexplained blood, fever, a persistent cough, night sweats or unplanned weight loss. Get advice sooner if you take blood thinners or have known lung disease.

Ask whether the blood could be from your nose, throat or lungs, whether your medicines alter bleeding risk, and what symptoms should send you straight to emergency care.