Thank you for your inquiry.
This is a difficult question to answer, and cannot be answered definitively. As you well know, children who have systemic reactions which are limited to the skin and subcutaneous tissue (urticaria/angioedema) when stung again have similar repeat reactions. Since these are not life-threatening (being limited to the skin and subcutaneous tissue), our Guidelines state that these children are not candidates for immunotherapy (1). So, the decision as to whether to begin immunotherapy depends upon whether one would label this reaction as being anaphylactic or systemic limited to the skin and subcutaneous tissue. The diagnosis of anaphylaxis would be made if there were manifestations in areas other than skin and subcutaneous tissue such eg, wheeze, fall in blood pressure, et cetera.
I assume that you are considering the symptom of "muffling of his voice" might be a systemic manifestation that would implicate laryngeal edema and therefore perhaps qualify him for immunotherapy. From your description, certainly there was no other manifestation pointing to a diagnosis of anaphylaxis (his blood pressure remained normal, there was no clear-cut shortness of breath or wheeze, no presyncopal symptoms, et cetera).
These observations make the interpretation of his history difficult, and I believe one could argue both sides of this issue effectively. That is, I think that some allergists-immunologists would choose to treat him with immunotherapy and others would withhold this treatment. There is no way to give you a definitive answer based upon the information available. But my strategy in these instances is to discuss the issues, and pros and cons, with the parents. I personally will usually administer immunotherapy if the parents are more comfortable with this option, and if they are happier with simple observation, I would have no problem following this strategy as well. I have found in most instances, parents are likely to favor the immunotherapy option, and this is usually my personal choice as well in cases which are borderline such as the one you present.
Thank you again for your inquiry and we hope this response is helpful to you.
1. Golden DBK, et al. Stinging insect hypersensitivity: a practice parameter update 2011. J Allergy Clin Immunol 2011; 127(4):852-854.
Phil Lieberman, M.D.