A retrospective chart review at a single institution included 388 patients who had 10,497 subcutaneous allergen immunotherapy (AIT) injection visits during a 2-year period.The rate of systemic reactions 0.28% per injection visit and 7.4% per patient (25 patients).
It was concerning that 48% of the systemic reactions occurred more than 30 minutes after the injection and many of these reactions required epinephrine.
This study was unable to identify risk factors that predict the reactions. Gender, phase (build-up versus maintenance), asthma, angiotensin-converting enzyme inhibitors, beta-blockers, initial skin-prick test size, or allergen type did not increase the odds of a systemic reaction.
Skin prick testing (SPT) on beta-blockers was safe in 199 patients in a 2012 study (http://goo.gl/3vGSl). However, incidence of systemic reactions is 1:250 with SPT.
References:
Allergen immunotherapy safety: Characterizing systemic reactions and identifying risk factors. Rank, Mathew A.; Oslie, Corrine L.; Krogman, Jennifer L.; Park, Miguel A.; Li, James T. Allergy and Asthma Proceedings, Volume 29, Number 4, 7/8 2008 , pp. 400-405(6).
The most recent SCIT-related fatal reaction occurred in 2007 - AAAAI http://goo.gl/k2QaN
Image source: OpenClipArt.org, public domain.
Image source: OpenClipArt.org, public domain.