Role of premedication to prevent reactions in cluster immunotherapy

Introduction: The clinical efficacy of allergen immunotherapy is well documented, but the treatment always involves a risk of adverse reactions. Although premedication is not routinely performed, it has been shown to reduce the adverse reactions. Aim: To evaluate the contribution of premedication to prevent hypersensitivity reactions during cluster im-munotherapy. Material and methods: 253 patients receiving a total of 290 cluster immunotherapy protocols to house dust mites, pollens, and venoms were recruited in the study. Patients were randomized into 5 groups according to the premedication status as follows: daily antihistamine, antihistamine only 2 h prior to injections, daily montelukast, combination of montelukast and antihistamine and the control group including patients without premedication. Patients were followed during up-dosing and maintenance phases of immunotherapy. Systemic and local reactions were reported. Results: Most of the patients were female (61.7%), the most frequent allergen was house dust mites (56.9%). 67.2% of patients had premedication and 20.6% of patients had reactions during the up-dosing phase. Reac-tions were more frequent in patients who received pollen immunotherapy. The total frequency of the hyper-sensitivity reaction was significantly higher in the control group. When evaluated seperately, local reactions were more frequently observed in the control group, while no difference in the frequency of systemic reactions was detected. Conclusions: Our study suggests that the reaction risk is increased in pollen immunotherapy. Premedication does not seem to prevent the frequency or severity of systemic reactions. However premedication, daily AH intake in particular, decreases the frequency of local reactions.