Why your nose runs
The lining of the nose produces mucus to warm, humidify and clean the air you breathe. It is controlled by nerves that respond to temperature, irritants and immune signals. In rhinitis, the lining becomes inflamed or the nerves become over-sensitive, so it produces more watery mucus than usual. This can happen through an allergic reaction, an infection or non-allergic triggers. Most people have a normal “nasal cycle” in which one side is slightly more open than the other, but constant dripping is not normal and deserves attention if it affects daily life.
Allergic rhinitis
Allergic rhinitis is caused by an immune reaction to substances such as pollen (hay fever), house dust mites, animal dander or mould. It causes a runny or blocked nose, sneezing, itchy nose, eyes and throat, and sometimes a cough. Symptoms may be seasonal or year-round. Allergy testing (skin prick or blood tests) can identify triggers. Treatment includes reducing exposure, antihistamines, steroid nasal sprays and, for some people, immunotherapy. Our guide to a sore throat from allergies describes related symptoms.
Non-allergic and vasomotor rhinitis
In non-allergic rhinitis, allergy tests are negative, but the nose still runs or blocks. A common form is vasomotor rhinitis, in which the nerves of the nose overreact to triggers such as cold air, sudden temperature or humidity changes, spicy or hot food (gustatory rhinitis), alcohol, perfume, cleaning products, smoke and stress. It is more common in adults and older people. Saline rinses, avoiding triggers, steroid sprays and an ipratropium nasal spray, which reduces watery secretions, can help. See vasomotor rhinitis and non-allergic rhinitis for more detail.
Other causes of a constant runny nose
- Repeated colds: especially in parents of young children and people working with the public.
- Cold weather: “skier’s nose” from cold, dry air.
- Eating: hot or spicy foods trigger a watery drip in many people.
- Ageing: older adults often have a constant clear drip, sometimes called senile rhinitis.
- Hormonal changes: pregnancy, the contraceptive pill and an underactive thyroid.
- Medicines: some blood pressure tablets, anti-inflammatories and erectile dysfunction medicines.
- Decongestant spray overuse: rebound congestion and drip after more than a few days of use.
- Chronic sinusitis and nasal polyps: thicker mucus, blockage and reduced smell.
- Cerebrospinal fluid leak: rare; clear, one-sided drip that may increase when bending forward.
Clues to the cause
- Itchy eyes, sneezing and seasonal pattern: allergy.
- Triggered by cold, food or smells, no itch: non-allergic rhinitis.
- Thick yellow or green mucus with facial pain: infection or sinusitis.
- Blockage and loss of smell: polyps or chronic sinusitis.
- Started after a new medicine: possible side effect.
- One side only, persistent: needs examination.
What helps a runny nose that never stops
- Keep a symptom diary to identify triggers.
- Use saline sprays or rinses daily to clear mucus and irritants.
- Try a non-drowsy antihistamine if allergy is likely.
- Use a steroid nasal spray regularly for a few weeks; it works best with consistent use.
- Ask a doctor about an ipratropium spray for watery drip triggered by food or cold.
- Avoid smoke and strong fragrances; wear a scarf over the nose in cold air.
- Stop decongestant sprays after a few days of use.
- Review your medicines with a pharmacist or doctor.
When to see a doctor
See a GP if a runny nose lasts more than a few weeks, affects sleep, work or quality of life, does not respond to simple treatments, or comes with blockage, reduced smell, nosebleeds or facial pain. An ENT specialist may examine the inside of the nose with a camera, arrange allergy tests or imaging, and test fluid if a cerebrospinal fluid leak is suspected. Treatments are effective for most people once the cause is clear. Ways to stop the drip quickly are covered in our guide on how to stop a runny nose.
Three common situations
- Nose runs every time you eat curry: gustatory rhinitis; an ipratropium spray before meals can help.
- Year-round runny nose and sneezing in the morning: dust mite allergy is likely; mattress covers, regular washing and a steroid spray help.
- Grandfather with a constant clear drip: age-related rhinitis is common; ipratropium spray and saline are often effective.
Key points to remember
- A constant runny nose is usually allergic or non-allergic rhinitis.
- Triggers such as cold air, food and smells point to non-allergic causes.
- Saline, antihistamines, steroid sprays and ipratropium help different types.
- A one-sided watery drip, especially after injury, needs medical assessment.
Questions about a constantly runny nose
These answers are general information and do not replace an examination or individual medical advice.
Why does my nose run when I eat?
Hot or spicy food stimulates nerves in the nose, causing a watery drip. This is called gustatory rhinitis and is harmless.
Why is my nose always runny but I am not sick?
Allergies, non-allergic rhinitis, cold air, ageing, hormones and medicines can all cause a runny nose without an infection.
Can a runny nose be a sign of something serious?
Rarely. A persistent clear, salty drip from one side, especially after head injury, may be cerebrospinal fluid and needs assessment.
Why does my nose run in cold weather?
Cold, dry air stimulates the nose to produce more mucus to warm and humidify it, and condensation adds to the drip.
Do nasal sprays make a runny nose worse?
Decongestant sprays used for more than a few days can cause rebound symptoms. Saline and steroid sprays do not have this effect.
Sources
This guide is for general information and does not replace medical advice. How a problem is diagnosed and treated depends on your examination and medical history. If you think you have an emergency, contact your local emergency services.