Thank you for your inquiry.
Obviously, we will not be able to give you a definitive answer as to the pathogenesis of the large local reaction in your patient. However, the most likely cause was an IgE-mediated late phase reaction. Over 50% of patients with large local reactions have demonstrable IgE antivenom (1).
In addition, such local reactions can be, like they were in your child, extremely large. Some are so large and occur so frequently that they can clearly diminish the quality of life of the individual involved (2).
Confirming the hypothesis that IgE plays a role in producing these reactions, it has been shown that venom immunotherapy can effectively diminish the severity of these local reactions (2, 3, 4).
Thus, my best guess is that your patient experienced a large, IgE-mediated late-phase reaction. Other possibilities also exist, but would be less likely. For example, an immune complex (Arthus) like reaction could have occurred based upon the fact that your patient had been stung previously and therefore might have circulating IgG antibody against venom. However, such reactions have not been demonstrated with the frequency of IgE-mediated events and, therefore, my opinion is that he probably experienced the IgE-mediated type event described above.
Thank you again for your inquiry and we hope this response is helpful to you.
1. Maurielo P et alNatural history of large local reactions from stinging insects. J Allergy Clin Immunol 1984 (October); Volume 74(4): 494-498 (Part 1).
2. Golden DBK, Kelly D, Hamilton RG, Craig TJ. Venom immunotherapy reduces large local reactions to insect stings. J Allergy Clin Immunol 2009;123:1371-5.(IIa).
3. Severino MG, Cortellini G, Bonadonna P, Francescato E, Panzini I, Macchia D, et al. Sublingual immunotherapy for large local reactions caused by honeybee sting: a double-blind placebo-controlled trial. J Allergy Clin Immunol 2008; 122:44-8. (Ib).
4. Walker R, Jacobs J, Tankersly M, Hagan L, Freeman T. Rush immunotherapy for the prevention of large local reactions secondary to imported fire ant stings. J Allergy Clin Immunol 1999;103(suppl):S180. (IIb).
Phil Lieberman, M.D.