In some people their allergic rhinitis symptoms happen all year round. This condition is called "perennial allergic rhinitis". This is usually caused by an allergens present in everyday life.

The major indoor allergens that cause perennial rhinitis are the house dust mite and materials shed from the bodies of furry and feathery animals (dander). Other things that can cause problems all year round are moulds, certain chemicals and some foods.

Unfortunately, identifying the allergens that cause perennial problems can be very difficult. Keeping a record or diary of times when symptoms are worse and where this happens may help identify the allergen. These findings can then be useful in discussions with a doctor or nurse.