Coughing up a little blood: what to know

Blood may appear as a red streak mixed with mucus after forceful or repeated coughing. A recent cold, acute bronchitis, asthma flare, post-nasal irritation or acid reflux can irritate nearby tissues. Bronchiectasis and a chronic cough can also produce blood-stained phlegm. These possibilities cannot be separated safely from the appearance of the sputum alone.

Notice whether the blood is bright red or dark, mixed through mucus or separate, and whether it came after a nosebleed or vomiting. A cough that brings up frothy blood, or blood with chest discomfort, breathlessness, faintness or fever, deserves urgent attention.

Stop smoking or vaping while you arrange advice, rest your voice, and sip fluids if swallowing is comfortable. Do not force a cough to clear mucus. Record when it happened, how much you saw, and any medicines that affect bleeding, including prescribed blood thinners. Arrange a prompt clinical review even when the amount was small if it happens again, lasts beyond a brief episode, or you have an ongoing cough.

Seek emergency help now if bleeding is more than a few streaks, continues, or makes breathing difficult. Go urgently as well for chest pain, a very fast heartbeat, severe weakness, confusion, fainting, or blue lips. If you feel stable but see blood again, contact a clinician promptly for an examination and possible chest testing. Do not drive yourself if you are dizzy or struggling to breathe.

Ask whether the blood seems to come from the lungs, throat or nose; whether your medicines could contribute; and whether your cough, wheeze or reflux needs a separate review. Bring a list of medicines and describe the timing, colour and amount as accurately as you can.