Anaphylactic shock secondary to rattlesnake bite.

Anaphylactic reactions to Crotalidae envenomation are extremely rare. The presentation of anaphylaxis after envenomation can be a confusing variable in the timely diagnosis of both problems. The therapy of this dual disorder involves combining treatment of the obvious shock from the allergic reaction with a standard approach to Crotalidae envenomation. We present the case of a 22-year-old man who presented to the emergency department with urticaria, hypotension, and bronchospasm that developed immediately after his second envenomation from a rattlesnake. His symptoms resolved after administration of 0.8 mg SQ epinephrine, 100 mg IV diphenhydramine, 2,000 mL normal saline IV, and 250 mg IV methylprednisolone. Only one previous case report of anaphylactic shock from a rattlesnake bite could be found in the medical literature.