Coughing up blood when you have a cold

Dry nasal passages, a nosebleed draining backward, or repeated forceful coughing can leave a small red streak in mucus during a cold. Blood may also indicate a lower-airway infection such as pneumonia, or another condition such as bronchiectasis, tuberculosis, a pulmonary embolism, or lung cancer. A cold does not prove that the blood is harmless. Pay attention to fever, worsening cough, breathlessness, chest pain, and whether the blood is coming from the mouth or nose rather than the chest.

Rest, drink fluids if you can, and avoid smoke or other airway irritants. Sit upright when coughing and record the colour, amount, and number of episodes. If your nose is dry or bleeding, gentle pressure and suitable humidification may help, but do not put objects deep into the nose. Arrange medical advice if blood returns, the cough worsens, or the illness is not settling. Use medicines only as directed, especially if you take treatment that affects clotting.

Seek emergency help for difficulty breathing, chest pain, faintness, confusion, blue lips, a fast heartbeat, or more than a small streak of blood. Urgent assessment is also needed when bleeding keeps recurring, you cough up clots, or you feel markedly unwell. Do not wait for cold symptoms to finish before seeking help for these warning signs.

Ask whether the blood appears to come from the nose, throat, or chest, and whether your chest needs examination or imaging. Mention fever, wheeze, breathlessness, smoking, previous lung disease, recent travel, and medicines that affect clotting. Ask how to monitor the cough and when to return.