Safety of subcutaneous specific immunotherapy with pollen allergen extracts for respiratory allergy

Background: Specific immunotherapy (SIT) is a well-documented treatment for respiratory allergy. However, the major risk of SIT is the development of systemic anaphylactic reactions. Objectives: To evaluate the safety of SIT given by subcutaneous route for 3 years to patients with seasonal allergic rhinitis (AR) with or without asthma. Methods: A prospective open-label study of immunotherapy ( Chenopodium album, Bermuda grass, or both) in 181 consecutive patients with AR with or without asthma. After an initial dose-escalation phase, a maintenance dose of 0.5 ml of 100,000 PNU/ml was administered monthly for 3 years. The occurrence and severity of systemic reaction (SR) and local reaction was recorded and graded according to the WHO position paper. Results: Of 181 patients enrolled, 57 (31%) did not complete the study ( 53 due to poor compliance and 4 due to systemic side effects). All 4 patients who developed SR had asthma and all the SR occurred during the dose-escalation phase. Three patients had moderate SR ( grade 2), while 1 patient had severe reaction ( grade 3). Three of the SR occurred within the first 20 min after injection and 1 SR occurred 2 h after injection. None of the reactions were life threatening and were managed easily. Total rhinitis symptom score decreased from 11.8 at baseline to 7.46 at the end of treatment (p < 0.001). The size of the skin prick test reaction to the main sensitising allergen was reduced from 7.48 +/- 2.26 mm at baseline to 5.60 +/- 2.18 mm at the end of treatment, p < 001. Conclusion: If a strict protocol is used, SIT is safe in AR patients with or without mild asthma and may result in significant subjective and objective improvement. Copyright (C) 2003 S. Karger AG, Basel.