Why does allergic rhinitis cause runny nose?

When pollen, dust mites, animal dander, or another allergen reaches the nose, the immune system can treat it as a threat. Cells in the nasal lining release chemical signals, including histamine. Blood vessels become leakier and glands produce more fluid, so clear mucus can drip from the nostrils or down the back of the throat. Runny Nose is a very common presentation of Allergic Rhinitis. The discharge is often thin and may occur with itching, sneezing, or a blocked feeling, but these symptoms can also have other causes.

Notice where and when symptoms start, such as after cleaning, around pets, or outdoors during certain seasons. Reducing exposure can help: keep windows closed when airborne triggers are troublesome, shower after outdoor activity, and wash bedding regularly. A saline nasal rinse or spray may clear mucus and irritants; use sterile, distilled, or previously boiled and cooled water for rinsing. A pharmacist or clinician can help you choose an antihistamine or nasal treatment that fits your symptoms and other medicines.

Arrange a medical review if symptoms disrupt sleep, work, school, or persist despite avoiding likely triggers. Seek prompt care for facial swelling, high fever, severe facial pain, thick discoloured discharge with feeling very unwell, or worsening breathing. Get emergency help for swelling of the lips, tongue, or throat, trouble breathing, faintness, or widespread hives, as these can accompany a serious allergic reaction.

Ask whether your pattern suggests allergy, a viral illness, sinus disease, or another nasal problem. Bring a short symptom diary and ask how to use nasal sprays correctly, whether allergy testing would be useful, and which treatments are suitable if you are pregnant, breastfeeding, or managing another long-term condition.