Blood in sputum and lung cancer

The blood may look like fine red streaks, small spots, or a larger amount mixed with mucus. Its appearance alone cannot identify the cause.

Lung cancer can present with blood-streaked sputum when a tumour irritates or bleeds into an airway. Chest infections, inflamed airways, a forceful cough, blood-thinning medicines, and bleeding from the nose or mouth can produce a similar finding.

A clinician will clarify whether the blood was coughed up rather than vomited or drained from the nose. They may examine the chest, review medicines and smoking history, and arrange chest imaging or other tests according to the findings.

Contact a clinician promptly even if there are only a few streaks, especially when the bleeding returns or comes with a persistent cough, chest discomfort, breathlessness, unexplained weight loss, fever, or a hoarse voice.

Note when the bleeding began, roughly how much appeared, its colour, and whether it was mixed with mucus. Bring an up-to-date medicines list and mention any recent infection, nosebleed, chest procedure, or known lung condition. Do not stop a prescribed blood thinner without medical instructions.

Call emergency services if you cough up more than small streaks, the bleeding is continuing, or breathing becomes difficult. Chest pain, fainting, severe weakness, confusion, blue or grey lips, or a very fast heartbeat alongside bleeding also require emergency assessment.

Sit upright, avoid driving yourself, and keep the airway clear while help is arranged. If possible, tell the emergency team about blood-thinning medicines and any lung cancer treatment you are receiving.

Ask which source of bleeding seems most likely, what examination or imaging is appropriate, and what change should trigger emergency care. If you have lung cancer, ask whether the bleeding could relate to the tumour, an infection, or treatment, and whether your current medicines need adjustment.