Thank you for your inquiry.
Although there is very rare mention here in the lay-directed Internet of prolonged itching after hymenoptera stings, there is no mention of this phenomenon in the medical literature in spite of extensive and comprehensive reviews of unusual reactions to hymenoptera stings.
Perhaps the most recent and comprehensive of all of these is by Dr. Robert Reisman entitled “Unusual Reactions to Insect Stings,” in Current Opinion Allergy and Clinical Immunology 2005; 5:355-358. In his review, he mentions a number of unusual reactions including delayed onset of acute encephalopathy and other neurological reactions including myasthenia gravis, peripheral neuritis, and Guillain-Barré syndrome. In addition renal failure, nephrotic syndrome, myocardial infarction, rhabdomyolysis, alveolar hemorrhage, thrombocytopenic purpura, vasculitis, corneal pathology leading to cataracts, and optic neuropathy are discussed. But there is no mention of any reported cases of prolonged or delayed onset pruritus.
Also there is a significant incidence of sensitivity without clinical reactivity to insect venom as assessed by skin and in vitro tests, especially after a sting. This makes testing difficult to interpret. Finally we have no idea as to the pathogenesis of this patient’s pruritus. By that I mean if it was IgE mediated.
All of these issues make me feel that there is not enough evidence to support immunotherapy in your patient.
In truth, the above is simply a matter of clinical opinion based on what is truly a dearth of information in the literature, and I am sure that one could marshal arguments against this interpretation. But in summary, in my opinion, I would not offer testing.
Thank you again for your inquiry and we hope this response is helpful to you.
Phil Lieberman, M.D.