The lining of the nose warms and moistens every breath, and it is controlled by nerves that respond quickly to temperature, spice and smell. With age, that control tends to become more sensitive, and the nose can start producing clear, watery drainage in situations that never used to trigger it.
The usual triggers
Hot or spicy food, cold outdoor air, strong perfume, smoke, a sudden change in temperature and alcohol are the most common. Doctors often call this non-allergic rhinitis — the nose behaves as if it were allergic, but no allergy is involved.
How it differs from an allergy or a cold
Allergies usually bring itching, sneezing fits and seasonal timing. Colds come with a sore throat and last about a week. The gustatory drip, as it is sometimes called, starts within minutes of the trigger and stops soon after.
What to look out for
Drainage that is only on one side, bloody, thick and coloured for weeks, or accompanied by facial pain or a blocked nose that never clears is different and worth having examined.
What helps
Noticing and avoiding the main triggers, a scarf over the nose in cold weather, and saline rinses help many people. A pharmacist or doctor can suggest nasal sprays that reduce the drip if it is bothersome.
A small reassurance
For most people this is a nuisance, not a sign of anything wrong. Keeping a tissue within reach at dinner is often the whole solution.