Bloody phlegm and sore throat: what to know

A dry cough, forceful throat-clearing, mouth breathing, or inflamed tonsils can break tiny surface blood vessels. Blood may also run down from the nose and mix with mucus, so the throat is not always the source. Viral illnesses such as a common cold, influenza, COVID-19, or glandular fever can inflame the throat. Allergic rhinitis and acid reflux may cause ongoing irritation. Strep throat and tonsillitis are possible when pain, fever, swollen glands, or difficulty swallowing accompany the bleeding. A sore throat is a common presentation of these conditions; it does not by itself identify the cause.

Note whether the blood is bright red or darker, mixed through mucus or only on its surface, and whether it follows coughing, vomiting, nosebleeding, or brushing your teeth. Sip water, avoid smoking and vaping, and use a humidifier if the air is dry. Choose soft foods and avoid repeated forceful throat-clearing. Do not start leftover antibiotics; treatment depends on the cause. Arrange a clinical review if the symptom keeps returning, the sore throat is worsening, or you have a condition or medicine that increases bleeding.

Seek urgent help for more than a small streak of blood, bleeding that does not stop, breathing difficulty, choking, inability to swallow saliva, severe weakness, chest pain, or sudden dizziness. Get prompt medical advice if you cough up blood from the chest, have a high fever with worsening illness, or the blood recurs without a clear source. A clinician can examine your mouth, throat, nose, and chest and decide whether testing is needed.

Could the blood be coming from my nose, gums, throat, or chest? What signs would suggest tonsillitis or strep throat? Do I need a throat swab or chest assessment? Which medicines should I avoid while this is happening?