Incidence of Immediate Hypersensitivity Reaction and Serum Sickness Following Administration of Crotalidae Polyvalent Immune Fab Antivenom: A Meta-analysis
This systematic literature review and meta-analysis evaluated the incidence of hypersensitivity and serum sickness reactions after receiving the Crotalidae polyvalent immune antivenom. This highly purified antivenom is produced in sheep models and is specific for 4 types of North American crotaline snakes: Western Diamondback rattlesnake, Eastern Diamondback rattlesnake, Mojave rattlesnake, and Cottonmouth snake. After systematic literature review by medical toxicologists, 11 studies were selected that examined North American crotaline envenomation and subsequent patient reactions.
When the highly purified crotaline antivenom was approved in 2000, the US Food and Drug Administration stated that incidence of hypersensitivity reaction and serum sickness to be 0.14 and 0.18, respectively. This meta-analysis found the incidence of hypersensitivity reaction to be 0.08, with a rash being the most common symptom. Additionally, the incidence of serum sickness was 0.13; however, the lack of systematic follow-up and prolonged time course led to more variability in the selected studies. Other limitations of this study include the small number of studies reviewed and the uncertainty whether symptoms were caused by the venom or antivenom. In conclusion, this meta-analysis found the incidence of hypersensitivity reaction and serum sickness after Crotalidae antivenom administration to be lower than initial reports from the US Food and Drug Administration.
Acad Emerg Med. 2012;19:121-131). TH Schaeffer, V Khatri, LM Reifler, EJ Lavonas.
Prepared by Matthew Stewart, MD, University of Utah Emergency Medicine Resident, Salt Lake City, UT, USA