What should you know about dark red nosebleed?

Blood can look dark red when it has remained in the nasal passage before coming out, mixed with mucus, or flowed slowly. Dry air, nose picking, forceful blowing, allergies, a cold, or sinus irritation can make the delicate nasal lining bleed. Blood may also come from deeper in the nose, where it can run into the throat rather than out of the nostril. Medicines that affect clotting and uncontrolled blood pressure can make bleeding harder to stop, though a nosebleed alone cannot identify either cause.

Sit upright, lean slightly forward, and breathe through your mouth. Pinch the soft part of the nose continuously for a full period without checking repeatedly. Spit out blood that reaches the mouth rather than swallowing it. A cool compress may be comfortable. After it stops, avoid nose blowing, picking, heavy exertion, and hot drinks for a while. Do not tilt the head back or pack the nose with tissues. Ask a clinician before changing prescribed blood-thinning medicine.

Seek emergency help if bleeding is heavy, follows a significant injury, causes faintness or breathing difficulty, or does not stop after sustained pressure. Get prompt medical advice for repeated episodes, blood flowing mainly into the throat, easy bruising, or use of anticoagulant medicine. Dryness and allergic rhinitis can contribute, while sinusitis or a common cold may irritate the lining; persistent recurrence deserves an examination.

Where is the bleeding coming from? Could dryness, allergy, infection, blood pressure, or a medicine be contributing? How should I prevent another episode, and when should my blood pressure or clotting be checked?