Pro and contra of specific hyposensitization.

Specific hyposensitization is the practice of administering gradually increasing quantities of a specifically relevant allergen to allergic patients until reaching a maintenance dose or loss of symptoms. The most important hypothesis regarding the mechanism is a switch from a Th 2- into a Th 1 reaction pattern in the T cell regulation. The efficacy of specific hyposensitization has been assessed in controlled studies. Allergen extracts are obtained by extraction of the active constituents from animal or vegetable substances with a suitable menstruum. There is a great assortment of different allergen extracts available, but only standardized extracts should be used. Specific hyposensitization is a causal treatment for patients with IgE-mediated allergies like seasonal or perennial allergic rhino-conjunctivitis, asthma or hymenoptera venom allergy. The principal and most effective route of allergen application is the subcutaneous injection. The risk of side effects, especially life threatening anaphylaxis must be considered and can be minimized by careful allergology practice. Oral/sublingual application of allergen extracts is still discussed controversially. Specific hyposensitization requires the high motivation and cooperation of an informed patient.