It is now known that there is a close link between asthma and allergies. Both conditions are caused by inflammation in the body. They also share many of the same triggers, especially allergens that are carried in the air, such as plant pollens, indoor and outdoor moulds, house dust mites and materials shed from the bodies of furry and feathery animals (dander).

The form of allergy that is most often linked with asthma is allergic rhinitis. Research has shown that as many as eight out of ten asthma patients also have allergic rhinitis.