Q:

12/26/2018
I have a 41 year-old male patient with history of a systemic allergic reaction - swelling of hands and face, throat tightness and difficulty breathing within a few minutes after he was stung by a bee on his foot about 20 years ago while working at his grandfather's bee farm. He could not remember if he had hives, GI symptoms or dizziness. He was taken to ER and was treated with epinephrine. He was sure that he was stung by a bee on that occasion, however could not remember if the bee died after it stung him. He had been stung by bees on many occasions while working prior to that and only had mild localized reactions. He never underwent immunotherapy or testing for venom allergy. He simply avoided the farm. He has only been stung by a wasp since. No reaction.

Now he is very interested in keeping bees. He is otherwise healthy. No medications, history of hives or mastocytosis. Skin and blood tests for all hymenoptera venom are negative now. I can think of these options for managing this case (other than discouraging him from bee keeping):
1: Only reassure him that tests are negative so at this point only carry Epipen(s). I am reluctant to do that.
2: Given tests could be falsely negative and the high chance for him to get stung if he starts bee keeping, should I arrange for venom challenge (graded challenge with venom injections or a sting challenge in the clinic)? I understand these are not routinely done.

A:

Unfortunately, there is no specific information to provide guidance for you in this decision. It is most likely your patient is not allergic to honey bee based upon the time since the sting, assuming it was a honey bee, and the negative tests. Short of a sting challenge which I would not recommend, I feel you have answered that question.

However, predicting the future is challenging. I would predict your patient is at greater than average risk of becoming bee sting allergic if stung. For that reason, I would suggest epinephrine autoinjectors be available as he initiates his beekeeping enterprise, recognizing the sensitivity may not develop, I would also verify that his baseline tryptase is not increased, as this would increase his risk of severe reactions (1). The work of Dr. Mubeccel Akdis and Ulrich Muller have shown that specific-IgE and other immune effects fluctuate with bee stings (2,3). Therefore, it is very possible specific-IgE to honey bee may increase. However, I do not think there is any value in screening periodically since without a history of a reaction, the predictive value of testing is of low value (3,4).

In summary, I do not think a sting challenge is necessary and you can reassure your patient he is not currently honey bee allergic. However, in my opinion, he is at increased risk of becoming allergic to honey bee stings and I would document a shared decision making discussion reviewing this issue. I would provide epinephrine autoinjectors “just in case”, measure a baseline tryptase to provide additional information as to degree of risk, and advise repeat assessment if systemic symptoms develop following stings. Dr. Muller’s work suggests that more than 10 stings in a season, atopic background and increased allergic respiratory symptoms during work with the bee hives increases probability of reactions (3).

1. Kucharewicz, I., et al. "Basal serum tryptase level correlates with severity of hymenoptera sting and age." Journal of investigational allergology and clinical immunology 17.2 (2007): 65.
2. Meiler, Flurina, et al. "In vivo switch to IL-10–secreting T regulatory cells in high dose allergen exposure." Journal of Experimental Medicine 205.12 (2008): 2887-2898.
3. Müller, Ulrich R. "Bee venom allergy in beekeepers and their family members." Current opinion in allergy and clinical immunology 5.4 (2005): 343-347.
4. Golden, David BK, et al. "Epidemiology of insect venom sensitivity." Jama 262.2 (1989): 240-244.

I hope this information is of help to you and your practice.

All my best.
Dennis K. Ledford, MD, FAAAAI

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