Venomous snakebite in a patient allergic to horse serum

The management of snake envenomation is a clinical challenge. The definitive therapy, antivenin, is potentially harmful and should not be used indiscriminately. However, the morbidity and mortality from the envenomation usually outweigh any adverse reactions to the antivenin therapy. Most reactions can be divided into two general categories: type I (immediate hypersensitivity) reaction, which may be life-threatening, and the more common type III (immune complex) reaction characterized by serum sickness. It is vital to evaluate the patient's potential for developing adverse reactions from antivenin and to be prepared to provide appropriate therapy. The administration of epinephrine and antihistamines can be lifesaving in type I reactions, while steroids and antihistamines can ameliorate type III reactions.