Allergic rhinitis is inflammation of the nose resulting from an allergy.
It affects five to 10 per cent of the population. A very common form is hay fever. It is not known why people develop allergic rhinitis. It is more common in people from families with eczema and asthma and there is probably an inherited factor that affects the way the immune system reacts to allergens. Allergic rhinitis results in a runny, itchy and blocked nose.