What should you know about blood in sputum?

Small red streaks may appear after forceful or repeated coughing has irritated the lining of the breathing tubes. Respiratory infections such as acute bronchitis or pneumonia can inflame these tissues. Bronchiectasis and COPD may also cause recurring phlegm with blood. Blood from a nosebleed or irritated sinuses can drain backward and be mixed with mucus before you cough it out. A clinician may need to distinguish blood coughed up from the chest from blood coming from the mouth, nose, or stomach.

The appearance can help describe the episode, but it cannot identify the cause by itself. Note whether the material is bright red or dark, mixed through sputum or on its surface, and whether it has happened again.

Stop smoking and avoid smoke or dusty air while symptoms are present. Sip fluids if swallowing is comfortable, and avoid repeatedly clearing your throat because this can cause more irritation. Record when the bleeding occurred, how much you saw, and any fever, chest discomfort, breathlessness, or weight change. Arrange medical advice for unexplained blood, especially when it recurs or you have a long-term lung condition. Do not start leftover antibiotics; treatment depends on the cause, and antibiotics do not treat every cough.

Seek emergency help if you are coughing up more than a small streak, the bleeding is continuing, or you have trouble breathing, chest pain, faintness, confusion, or blue lips. Urgent assessment is also needed if blood appears after a chest injury or alongside severe illness. Even a small amount deserves prompt clinical advice when it keeps returning, occurs with persistent fever, or is associated with worsening cough.

Ask whether the blood seems to come from the lungs, throat, or nose; which examination or tests are appropriate; and whether your medicines could increase bleeding. You can also ask what changes should prompt emergency care and whether a review of your inhalers or smoking exposure is needed.