Background: The efficacy of subcutaneous immunotherapy for the treatment of allergic rhinitis, allergic conjunctivitis, allergic asthma and stinging insect hypersensitivity has been demonstrated in several studies.

Objectives: To investigate the effectiveness and side effects of immunotherapy in Israel and the relationship between local and systemic side effects.

Methods: This retrospective study was based on patient records and a computerized database for drug dispensing over a 5 year period. Success was rated as partial or complete. Side effects were classified as local or systemic. Systemic side effects were further classified according to severity, as mild (cutaneous), moderate (respiratory symptoms), or severe (cardiovascular).

Results: Of the 135 patients on aero-allergen immunotherapy who reached maintenance, 120 (88.9%) exhibited complete or partial improvement and 15 (11.1%) did not improve. All of the 44 patients on hymenoptera immunotherapy reached effective maintenance doses. The mean percent side effects calculated per treatment (injection) were 2.49 for local and 1.58 for a systemic reaction during the build-up phase, and 1.13 and 1.12 during the maintenance phase, respectively. Rates of systemic reactions were 1.3% for cutaneous, 1.14% for respiratory and 0.97% for cardiovascular reactions during the build-up phase, and 1.11%, 0.53%, and 0.51% during the maintenance phase, respectively. The odds of systemic reactions were significantly higher in patients with local reactions both in the build-up phase (P = 0.03) and in the maintenance phase (P = 0.0003). The number of annual medications dispensed per patient decreased from 31.5 to 26.0 during the first year after reaching maintenance, and to 22.5 in the second year. Pharmaceutical costs were 67% lower 1 year after the start of the maintenance phase, compared to the year before the start of immunotherapy, and 63% lower in the second year (P = NS).

Conclusions: Immunotherapy was effective and safe. Recognizing the benefits and safety of immunotherapy is necessary for physicians and health authorities in order to provide better care for allergic patients.