Surveillance of systemic reactions to subcutaneous immunotherapy injections: year 1 outcomes of the ACAAI and AAAAI collaborative study.

BACKGROUND: Although systemic reactions (SRs) to subcutaneous immunotherapy (SCIT) injections are not uncommon, life-threatening and fatal reactions are rare. The annual incidence of injection-related SRs of varying severity is not well-defined.
OBJECTIVE: To determine the annual frequencies of SCIT reactions in North America via a longitudinal surveillance program initiated among practicing allergists in 2008.
METHODS: Physicians were asked to complete a Web-based survey reporting numbers of injections administered, injection- and skin test-related fatal reactions, and all nonfatal SRs in their clinical practices during the previous 12 months. The SR events were classified as mild (grade 1: cutaneous or upper respiratory symptoms), moderate (grade 2: asthma with reduced lung function), or severe (grade 3: life-threatening airway compromise or hypotension).
RESULTS: In the initial year of the program, 806 physicians responded, representing 1,922 SCIT prescribers. No fatal reactions to SCIT injections were identified during the first 12 months, although 6 SCIT fatal reactions were reported retrospectively between 2001 and 2007. Eighty-two percent of practices reported 8,502 SRs to SCIT (10.2 SRs per 10,000 = 0.1% of injection visits). Most were grade 1 (74%) or grade 2 (23%) SRs. However, 3% (n = 265) were grade 3 anaphylactic events (3 severe reactions for every 100,000 injection visits).
CONCLUSIONS: We demonstrated the feasibility of annual surveillance of SRs associated with SCIT injections. This surveillance study will continue to monitor SCIT adverse events in parallel with vigorous efforts instituted by members of professional organizations aimed at reducing the risk of severe reactions.

RCT Entities:   Population Interventions Outcomes