Cough that smells like blood: what to know

A metallic or blood-like smell can come from a small nosebleed, irritated gums, a throat injury or mucus draining from the nose, even when the lungs are not bleeding. Acute bronchitis can irritate airway lining and cause streaks in phlegm. Bronchiectasis may cause recurrent mucus and bleeding from damaged airways. Asthma, allergic rhinitis or a common cold can make the throat and nose easier to irritate. Acid reflux may leave an unusual taste or smell but does not explain every episode. A smell alone cannot show where it began, so note whether you taste blood, see red or rust-coloured material, or have bleeding from the nose or mouth.

Stop smoking and avoid vigorous throat clearing. If blood appears, note its colour and approximate amount without swallowing it, and keep a photograph if safe to do so. Check the mouth and nose gently for an obvious source. Arrange medical advice for any unexplained episode, repeated blood-stained mucus, fever, worsening cough or breathlessness. Tell the clinician about blood-thinning medicines, recent dental work, nosebleeds and chest conditions.

Call emergency services for more than a small streak of blood, repeated coughing of blood, severe breathlessness, chest pain, faintness, confusion or blue or grey lips. Seek urgent care if bleeding follows a chest injury, comes with a very fast heartbeat, or is increasing. Do not wait for a routine appointment if you feel seriously unwell; sit upright and avoid driving yourself.

Could the smell be coming from my nose, mouth, throat or lungs? Do I need an examination or tests? Could any of my medicines increase bleeding? What should I do if blood appears again, and which amount or symptom is an emergency?