How do I differentiate between benign and serious causes of haemoptysis in primary care?

To differentiate between benign and serious causes of haemoptysis in primary care, consider the patient's age, smoking history, and associated symptoms. Haemoptysis that is unexplained in people aged 40 and over should be treated as potentially serious and warrants urgent referral via a suspected cancer pathway for lung cancer investigation. This is especially important if the patient has risk factors such as a history of smoking or asbestos exposure. Additionally, the presence of other symptoms such as persistent cough, chest pain, weight loss, or fatigue alongside haemoptysis increases the suspicion of lung cancer and necessitates urgent chest X-ray and referral. In contrast, haemoptysis in younger patients without risk factors and without concerning symptoms may be more likely due to benign causes such as infections or bronchitis, but clinical judgment and safety netting remain essential.