Thank you for your inquiry.
The questions that you asked, as stated, are posed from a clinical standpoint. Therefore I would like to recommend a text which addresses all of these questions from that standpoint. It is Patterson’s Allergic Diseases, 7th edition, edited by Dr. Leslie Grammer and Dr. Paul Greenberger, 2009. The chapter on Immunotherapy of that text appears on Page 187. Based upon the principles noted in this chapter, your questions are answered below in the order in which they appear in your inquiry:
1. Current evidence suggests that “treatment with higher doses of pollen extracts results in better long range reduction of clinical symptoms and greater immunologic changes than low dose therapy.” We can therefore make a general statement that the higher the dose, the more likely your patient will improve.
2. In clinical practice, one judges efficacy only on the basis of symptoms. No other modality is used.
3. Stated in Patterson’s text, “Patients who do not respond after receiving maintenance doses of immunotherapy for one year are unlikely to improve with further treatment. Therefore, immunotherapy should be discontinued in patients who have not had appreciable improvement after an entire year of maintenance doses.”
4. There are various schedules of immunotherapy. It is essential that you become familiar with these schedules. They are discussed in Patterson’s text, and another reference which presents these schedules is Middleton’s Allergy: Principles and Practice, 7th edition, 2009. The schedules are also discussed in a reference which is available online free of charge. This is Cox L, et al. Allergen immunotherapy: a practice parameter, third update. J Allergy Clin Immunol 2011; 127(1)Supplement:S1-S55.
Once you decide upon the schedule that you wish to use, shots are given at the frequency prescribed in the schedule, and then there is a tapering of the frequency of injections. The duration of immunotherapy is usually three to five years. Immunotherapy is normally stopped without repeating skin tests or any other testing.
Thank you again for your inquiry and we hope this response is helpful to you.
Phil Lieberman, M.D.