Regular use of these agents results in dependence and a rebound effect leading to greater congestion. Immunotherapy Immunotherapy , or allergy shots, involves a series of injections of those substances which trigger allergic symptoms. They are tailor-made for the individual. When effective, shots are administered for at least five years. Immunotherapy is not without risk.
Local reactions resembling a mosquito bite are common.
Systemic reactions, a severe allergic reaction, may consist of hives, wheezing, difficulty breathing, and even low blood pressure. Such reactions occur about once every 1000 injections. Death, may occur, but is exceedingly rare. About one to two deaths occur nationwide due to immunotherapy annually. Immunotherapy is also inconvenient requiring frequent visits to the physician's office, at least for the first few months.