First employed in the 1920s, immunotherapy consists of injecting gradually larger amounts of the allergens that cause the patient's allergic response. At the beginning of the treatment the dose is intentionally much too small to cause a reaction. The dose is gradually increased to a level that protects the patient from whatever is causing the allergy. It usually takes six to 12 months to reach a protective dose. Whether or not the patients can successfully stop receiving allergy shots is uncertain.
Studies suggest that protection fades if the shots are discontinued.
For that reason, some allergy specialists recommend that they be continued indefinitely. Aiming for Improvements FDA is actively seeking to standardize the commercially available extracts used in skin testing and immunotherapy to improve their safety and effectiveness. Studies have shown, for example, that weed and grass pollen extracts are more than 10,000 times as potent in producing skin reactions as extracts made from white pine and mountain cedar pollen. Using single-allergen, standardized extracts, physicians are better able to tell precisely what causes a patient's symptoms and to plan, if necessary, the most effective course of allergy shots. Immunotherapy has proven effective in hay fever sufferers and can be little short of miraculous for some patients who cannot get adequate relief either from avoiding allergens or from medication.