What should you know about just a runny nose?

A runny nose happens when the lining of the nose produces extra fluid. A [Common Cold](/conditions/common-cold/) may bring congestion, sneezing, cough, or a scratchy throat. [Allergic Rhinitis](/conditions/allergic-rhinitis/) more often causes repeated sneezing, an itchy nose, and watery eyes after exposure to a trigger.

Symptoms that appear around dust, bedding, or pets may fit [House Dust Mite Allergy](/conditions/house-dust-mite-allergy/) or [Pet Allergy](/conditions/pet-allergy/). Facial pressure, reduced smell, or thick discharge can occur with [Sinusitis](/conditions/sinusitis/). Fever, body aches, or marked tiredness can occur with [Influenza](/conditions/influenza/) or [COVID-19](/conditions/covid-19/). These patterns overlap, so one symptom cannot diagnose the cause.

Drink fluids, rest, and use tissues gently. Saline drops or a saline nasal rinse may loosen mucus; use sterile or previously boiled and cooled water for a rinse and clean the device as directed. Avoid smoke and other irritants.

If allergy is suspected, reduce contact with the trigger and ask a pharmacist about suitable treatment. Decongestant sprays should not be used for longer than their label advises because congestion can rebound. Check combination cold products to avoid taking duplicate ingredients.

Seek urgent help for severe breathing difficulty, swelling of the face or throat, confusion, or a severe headache with neck stiffness. Arrange medical advice for symptoms that persist, repeatedly disturb sleep, follow a head injury, or come with one-sided bloody discharge.

A child who is struggling to breathe, feeding poorly, or unusually sleepy needs prompt assessment. Testing may be useful when a runny nose occurs with fever, cough, or known exposure to a respiratory infection.

Ask whether the pattern suggests infection or allergy, how to use a nasal treatment safely, whether testing is useful, and what duration or symptom change should prompt review.