Mastoparan as a Potential Cause of Hemolytic Anemia Due to a Suspected Single Wasp Sting in a Dog

Objective In people, severe Hymenoptera stings can lead to systemic allergic reactions, acute kidney injury, rhabdomyolysis, hemolysis, shock, and even death. Hemolytic anemia as a result of multiple honeybee stings has been reported in dogs; however, there are no prior reports of hemolytic anemia due to wasp stings in the dog. In this report, we present a case of a dog that developed hemolytic anemia after a single wasp sting. We also report the vulnerability of RBCs to the wasp venom using an in vitro hemolysis assay. Case Summary A 3‐year‐old neutered male Yorkshire Terrier presented with hemoglobinuria 4 h after a suspected single wasp sting and achieved complete remission after a short course of treatment with glucocorticoids and IV infusion, without long‐term sequelae. An in vitro hemolysis assay using mastoparan, a major wasp venom constituent, was performed to test our hypothesis that increased sensitivity of the RBC membrane to wasp venom would lead to hemolysis after exposure to a small amount of venom by a single sting. Although no difference in the amount of mastoparan leading to hemolysis in 50% of the RBCs (HC 50 ) was seen between the patient and two healthy controls, the HC 50 was higher in whole blood samples. New and Unique Information This is the first report demonstrating that even a single wasp sting can cause hemolysis in dogs. In addition, based on our in vitro hemolysis assay, plasma may have an inhibitory effect on mastoparan‐induced hemolysis.