Allergen-specific immunotherapy provides immediate, long-term and preventive clinical effects in children and adults: the effects of immunotherapy can be categorised by level of benefit -the centenary of allergen specific subcutaneous immunotherapy

Allergy is a systemic disease with a local response following allergen exposure. Rhinitis, asthma and Bronchial Hyperresponsiveness (BHR) are closely related and a systemic pathway, involving the bloodstream and bone marrow, contributing to the cross-talk between the upper and lower airways [1].The close relationship between allergic rhinitis and allergic asthma and the co-morbidity of upper and lower airway diseases has been carefully described elsewhere [2-4]. In asthmatic children it has been shown that asthma was more severe when in concomitance with allergic rhinitis and that increased asthma medication was required [5]. In asthmatic adults with concomitant allergic rhinitis asthma control is less manageable while there is a higher rate of asthma exacerbations and emergency room visits [6]. Allergic rhinitis is a major risk factor for the later development of asthma [3,7] and more than 20% of all rhinitis patients develop asthma later on in life [8]. Up to 50% of rhinitis patients have increased bronchial hyperresponsiveness during, as well as outside the pollen season [9] and an ongoing subclinical level of inflammation [10]. Allergic sensitivities usually increase with age [11] and being sensitised to one allergen source also increases the risk for developing new sensitizations over time [12]. The understanding of allergy as a chronic systemic immunological condition should be the platform for the choice of diagnostic, treatment as well as monitoring options in the allergic patient.Allergen specific immunotherapy (SIT) produces a decrease in symptoms and in the need for medication, but SIT also has the capacity for long-term clinical effects and for the prevention of the development of further allergies and symptoms. The treatment acts on the basic immunological mechanisms responsible for causing symptoms and has the potential to change the immune response and the pathological pathways responsible for the allergic symptoms [13]. SIT is an anti-inflammatory, c