Potential causes of blood in nasal passage mucus include dryness or irritation of the nose from picking, blowing or rubbing, explains WebMD. Blood within mucus commonly comes from the area of the nostril where blood vessels are located. Small amounts of blood within nasal passage mucus does not typically indicate an infection, but large volumes of blood need evaluation by a medical professional.
Individuals who have blood in nasal passage mucus on only one side of the nose should seek medical attention to evaluate if part of the nose is injured or a foreign object is lodged in the nose, according to Merck Manuals. Nasal congestion that produces mucus of any color is commonly due to viral upper respiratory infections, allergic reactions, sinus infections or an overuse of decongestant sprays.
Medical professionals determine the cause of nasal congestion, with or without blood in the nasal passage mucus, by assessing the nature of the discharge; the frequency of mucus; additional symptoms, such as itchy eyes or fever; and the overall health of the patient, explains Merck Manuals. Patients with sinusitis often experience face pain and fever, whereas itchy and watery eyes accompany mucus due to allergies. An individual with a viral upper respiratory infection commonly has a cough and fever, and a person with malaise experiences a general ill feeling.