Life-threatening anaphylaxis following envenomation by two different species of Crotalidae

Anaphylactic reaction to snake venom occurs rarely but is a risk in those victims with previous exposure to venomous snakes and their venom. We present the case of a herpetologist who suffered acute, life-threatening anaphylaxis on two separate occasions following envenomation by two different species of rattlesnake. On both occasions the patient received treatment for anaphylaxis within minutes of being bitten and responded well. Administration of crotalidae antivenin was unnecessary. Snake venom is a heterologous mixture of proteins and other chemicals and is able to provoke immune sensitization to its components in humans. Antigenic similarities are often present in venoms of different species. IgE and IgG have been demonstrated in sera from patients who have suffered snake venom anaphylaxis. This case testifies to the immunogenicity of rattlesnake venom across species.