Delayed reaction following an insect sting
Question:
11/13/2020
A 65 year-old who reported that after she was stung on her arm, she developed a large local reaction. By the following day as the local swelling became worse, she developed diffuse itchiness with itchy palms and difficulty breathing. Tryptase is normal and specific IgE to venoms is low positive to yellow jacket: 0.45 kU/L. IgE and skin testing negative for hornets, wasp and honeybee. Would you recommend venom immunotherapy for yellow jacket?
Answer:
Reactions occurring more than four hours after insect stings are classified as delayed reactions. Delayed reactions are briefly addressed in the 2017 practice parameter (1), but because these data are primarily case reports it did not meet criteria for inclusion as a statement.
In 1989, Dr Reisman(2) reported 10 patients with delayed reactions, 5 of which had generalized hives starting 6 to 24 hours after an insect sting. All 5 patients in this group had positive venom specific IgE, 3 of which received Venom Immunotherapy (VIT). In 1989 VIT was recommended in adults who experienced generalized urticaria following an insect sting, while this is no longer the recommendation.
More recently, Ghaffari, et al. (3) reported on a 32 year-old male firefighter with recurrent episodes of anaphylaxis immediately after being stung, which were followed by delayed anaphylactic reactions, ranging from a few hours to a few days. This case illustrates delayed, biphasic and protracted anaphylactic hypersensitivity reaction to insect stings. The patient was started on conventional VIT but struggled with recurrent reactions. Ultimately, he was successfully managed with rush VIT.
Data have shown that there is a marginally higher risk of subsequent systemic reaction in patients that experience LLR. VIT is considered only if events are frequent and/or result is significant morbidity, such inability to wear shoes following fire ant sting. That said, VIT has been shown to be effective in minimizing LLR. The patient in question developed worsening LLR, diffuse itching and respiratory distress the day after the initial sting and had a positive sIgE to Yellowjacket and had a normal tryptase. With involvement of a second organ system, pulmonary, I feel there is a risk for a potentially more severe reaction with subsequent sting and therefor VIT is warranted. Risk and benefit of VIT should be discussed with the patient and then proceed accordingly.
(1) Golden DB, Demain J, Freeman T, et al. Stinging insect hypersensitivity: A practice parameter update 2016. Ann Allergy Asthma Immunol. 2017 Jan;118(1):28-54.
(2) Reisman RE1, Livingston A. Late-onset allergic reactions, including serum sickness, after insect stings. J Allergy Clin Immunol. 1989 Sep;84(3):331-7.
(3) Ghaffari G, Craig T, Golden D, Chegini S. Delayed and recurrent anaphylactic reaction to yellowjacket sting [abstract]. J Allergy Clin Immunol. 2006;117:S309.
I hope you find this helpful,
Jeffrey G Demain, MD, FAAP, FACAAI, FAAAAI