Desensitisation (sometimes referred to as allergen immunotherapy or specific immunotherapy) is the foundation stone in respiratory allergic treatment.
Perfectly compatible with simultaneous management of symptoms with drugs, desensitisation is the only modality which can prevent and treat allergic disease. Moreover, it blocks exacerbation of the condition, (e.g. the degeneration over time of simple allergic rhinitis into full-blown asthma), and precludes complications (e.g. the development of hypersensitivity to other substances: polysensitisation).

It works by gradually modulating the body's immune response to the guilty allergen so the hypersensitive state steadily wanes. In this way, the allergic reaction is inhibited by desensitisation.

In recent years, desensitisation protocols have been conducted to evaluate the efficacy of the approach and determine precisely the scope of this form of treatment.

In 1998, the World Health Organisation (WHO) recognised desensitisation as being of therapeutic value, a great moment in the history of this approach. This Consensus Position based on the opinions of the world's leading experts in the field stipulated "Good Clinical Practices" guidelines for desensitisation, pertaining to both indications and protocols.

 Two different routes of administration are available:

• Subcutaneous injection: the traditional route of administration for specific immunotherapy, of thoroughly demonstrated efficacy;

• Sublingual administration: well tolerated and suitable for a broader range of patients: efficacy equivalent to that of subcutaneous injection. Administration takes place at home, in the morning before breakfast, by applying drops of the allergen solution directly under the tongue.