Allergic rhinitis (AR) is an allergen-induced, upper-airway inflammatory disease. The characteristic symptoms of allergic rhinitis are a runny nose, sneezing, congestion, redness of the eyes, watering eyes, and itching of the eyes, nose and throat. Previously, allergic rhinitis was subdivided into seasonal and perennial allergic rhinitis. The current classification of the World Health Organization (WHO) subdivides allergic rhinitis into intermittent allergic rhinitis and persistent allergic rhinitis (ARIA Guidelines). Intermittent allergic rhinitis occurs in people who are allergic to grass or tree pollen present during spring and summer (hay fever). Persistent allergic rhinitis results from the constant presence of allergens such as mold, animal dander or house dust mites. This type of allergic rhinitis occurs throughout the year, although symptoms may be less severe than with intermittent allergic rhinitis. This thesis focuses on persistent allergic rhinitis triggered by house dust mites in children. The majority of patients who seek medical advice visit their general practitioner. Although allergic rhinitis is not a life-threatening disease, it can have a significant effect on quality of life, and is associated with a number of common co-morbidities, including asthma and sinusitis.