Thank you for your inquiry.
I am going to ask Dr. David Golden for a response regarding your patient. As you know, Dr. Golden is a nationally known expert in hymenoptera allergy. As soon as we receive Dr. Golden’s response, we will forward it to you.
Thank you again for your inquiry.
Phil Lieberman, M.D.
We received a response from Dr. David Golden regarding your Ask the Expert inquiry. Thank you again for your inquiry and we hope this response is helpful to you.
Phil Lieberman, M.D.
Response from Dr. David Golden:
It is exceedingly rare, but not unheard of, to have delayed anaphylaxis to a sting, and the mechanism, of course, is unexplainable (theoretically, perhaps, T-cell mediated anaphylaxis to peptide components). I would have been skeptical about just subjective symptoms, but if there were hives, then there is objective evidence of reaction. If the skin tests wee convincingly positive at 12-18 hours, then it supports the diagnosis of delayed anaphylaxis (especially with the actual systemic symptoms after the skin test - did this include hives?). It sounds like repeating skin tests will not change anything. The Europeans would do a basophil activation test, and this might be available in the US (eg IBT labs) but it may not be covered by insurance.
Regardless, the practical question remains about VIT. I think I would have to recommend VIT to mixed vespid venom, although you could start with just yellow jacket. We could consider adding wasp venom later. I agree that there is an obvious chance of delayed reaction to VIT. I do not believe that starting at extremely low doses and building up exceedingly slowly will make any difference. In fact, repeated low doses may simply increase the sensitivity long before it would result in any beneficial immune response. That leads to the option of rush VIT using an in-patient desensitization protocol over 2-3 days with pre-medication (there are several references, especially Bernstein J et al, JACI 1994, and Goldberg A et al, JACI). There is one report of a patient who had anaphylaxis 4 hours after a sting, and 4 hours after skin tests and/or VIT, but had uneventful rush VIT and did well on maintenance VIT (Ghaffari et al. AAAAI abstract. JACI) Of course, you should consider trying a routine approach first because some patients do surprisingly well (perhaps due to less reaction to subcutaneous doses than to intradermal doses). If even rush VIT fails, Xolair would be worth a try prior to rush VIT (several reports of success).
I would be interested in a follow-up report on whatever course of action you take. Good luck.