Headache and spitting out blood

A small streak may follow a bleeding gum, mouth sore, nosebleed draining backward, throat irritation, or forceful coughing. Blood that is frothy, repeatedly coughed up, or mixed with phlegm may come from the airways. Vomited blood has a different source and can look dark or coffee-like. A headache may occur at the same time because of an infection, dehydration, fever, or strain, but it does not explain every episode of bleeding. The colour, amount, source, and recurrence matter.

Sit upright and spit blood into a tissue or container so you can observe whether it returns; do not swallow large amounts. Check gently for bleeding in the mouth and note whether blood follows coughing, vomiting, brushing, or a nosebleed. Avoid smoking, alcohol, strenuous activity, and medicines that you have been told to avoid when bleeding is present. Arrange prompt medical advice, especially if the source is unclear, the bleeding returns, or you take blood-thinning medicine.

Seek emergency help for more than a small streak, ongoing bleeding, coughing or vomiting blood, breathlessness, chest pain, faintness, confusion, severe weakness, or a sudden severe headache. Emergency assessment is also needed for a headache with weakness, speech trouble, seizure, or fever with a stiff neck. Do not drive yourself if you feel faint or unwell.

Where does the blood appear to be coming from? Could my medicines, gums, nose, chest, or stomach be involved? What should I do if it happens again?