Lessons From a Teen Food Allergy Tragedy
AL: What if a child or adult ingests a bit of an offending food, then spits it out and shows no symptoms?
RW: It depends on the individual, but I have large numbers of patients where their action plan does recommend automatic injection of epinephrine for any known exposure or even an expected exposure. In most instances, the more quickly it’s given, the better.
AL: When someone doesn’t have symptoms for 20 minutes, then suddenly goes into anaphylactic shock, what’s going on?
RW: Even when food is spit out, there is still absorption of the allergen in the mouth and throat, and the absorption typically happens over a period of 10 to 40 minutes. As that food is absorbed systemically, the chain of events that make up an allergic reaction are all put into effect. It can be delayed by up to two hours, but nearly all allergic reactions will begin in the first 30 minutes.
AL: A lot of people think they will feel the effects instantaneously.
RW: That’s often a localized reaction in their mouth and throat where they’ll feel itching very quickly. But systemic symptoms won’t happen instantly, because you have to absorb the food. You can see them within minutes, but 20 minutes would be a typical timeframe.
AL: What are the signs that tell you, “OK, time to inject”?
RW: For my patients, we talk about reactions that are very localized versus anything more than localized. Localized would be itching in the mouth, a few hives around their mouths, and nothing beyond that. Anything beyond localized, even just hives that are spreading, indicates a need for epinephrine.
Then certainly involvement of other systems in the body: if you’re having repetitive vomiting, any respiratory symptoms, then you would automatically get epinephrine. High-risk patients aren’t given any discretion: they’re advised to give the epinephrine automatically and immediately.
AL: Many people take antihistamines such as Benadryl as a first, and sometimes only, line of defense. What is your take? And can it mask symptoms?
RW: Antihistamine is a useful medication for some relief of symptoms such as a few hives, but has no capacity whatsoever to prevent or control more serious allergic reactions. If a reaction is going to progress, the administration of Benadryl will not help to prevent any real progression.
We don’t worry that it’s masking things; it’s not potent enough. So we don’t think there is any risk in giving it – except for the false sense of security that it might give, that it will help relieve or prevent a more dangerous reaction. It won’t do that at all.
Next: How safe is epinephrine?