Mild immediate reaction to wasp sting and delayed GI symptoms
Question:
12/28/2022
A 52-year-old male with reported wasp sting on abdomen with mild local reaction immediately, followed by severe abdominal pain, cramping, vomiting and diarrhea, elevated at 99-100F 3 hours after. Symptoms resolved the next day and he's been asymptomatic for months. History of local reactions with bee and yellow jacket stings as a child.
Labs: Tryptase 4, IgE 549, Aeroallergen panel positive for pollens, Venom IgE (White Face Hornet 3.95, Yellow Hornet <0.10, Paper Wasp 0.31, Honeybee 40.30, Yellow Jacket 0.69).
His presentation doesn’t seem consistent with an IgE mediated process. DDx also includes food poisoning (family members did not any any GI symptoms) vs toxic reaction vs serum sickness (though he did not have any joint pains). What do you think is the most likely explanation for his symptoms? He does also have positive venom IgE, so moving forward would you prescribe him an epinephrine autoinjector?
Answer:
The reaction is atypical for anaphylaxis and specific IgE to venom components could be associated with local reactions. The Stinging Insect Practice Parameter states, “The risk of a systemic reaction in patients who experience large local reactions is 4% to 10%.” Autoinjector epinephrine is not indicated for the local reactions described, since it is mild and presumably small. I would not expect a single sting to cause a toxic reaction or serum sickness.
In summary, I am not convinced that the gastrointestinal symptoms and fever are related to the wasp sting on the abdomen. I would reassure the patient and would discuss the role of epinephrine in treatment of anaphylaxis. I would not be opposed to providing if the patient was apprehensive about the uncertainty of what caused the reaction compounded by the positive allergy tests for venoms.
I have shared this response with an international expert on insect allergy, Dr. David Golden, who is past chair and current member of the Joint Task Force on Practice Parameters and co-chair of the writing group developing an practice parameter update on anaphylaxis. He agreed with the above and shared the following additional thoughts: If the abdominal symptoms occurred within 3 hours, then serum sickness cannot be the explanation. Toxic reactions can cause such symptoms, but usually after a larger number of stings (although not impossible from a single sting). I would not characterize the local reaction (as described) as being abnormal or allergic (ie, not a "large local reaction"). There was no evidence of anaphylaxis, so I would not have ordered the IgE tests (which can be positive in 30%-40% of people in the weeks after any sting). A positive test only proves he was stung. However, the lab tests do not support the identification of a “wasp”, but more likely a honey bee, or possibly a white-faced hornet. Was there a stinger left in the skin (ie, honeybee)? Regarding the epinephrine, it is not required because the risk of anaphylaxis is relatively low in someone with positive venom-IgE but no history of anaphylaxis, but the option can be presented for shared decision making based on the patient’s values and preferences and any known high-risk factors.
Carla M. Davis, MD, FAAAAI