Type I Hypersensitivity

November 6, 2018

I had another allergic reaction, once again after specifically inquiring  about a dish’s peanut content. I noticed suspiciously peanut-like “macadamia nut” pieces that tasted an awful lot like peanuts to my companion, but after being assured they were not peanuts, the first bite determined that was a lie. Perhaps it was the sauce? I haven’t seen poke with peanut sauce before but hey, there’s always a first time.

One might think it would be obvious that someone asking about a a food ingredient due to a peanut allergy would be interested to know if some other component of the dish was, say, peanut. I’m beginning to wonder if restauranteurs in San Diego know what peanuts are.

Regardless, having been reassured that there were no peanuts, I took a big, delicious bite, telling my friend, “I would know by now if there was…” Which is precisely when I began noticing the reaction. It was fast and bad. I didn’t have my EpiPen with me because of style: my messenger bag is breaking down, starting with the zippers. Instead, I slammed two diphenhydramine and excused myself to the bathroom to throw up while we waited for the check.


Flashback: one month ago

I did an elective rotation in Allergy and Immunology, in part due to self-interested curiosity. One of the many fantastic attending physicians I worked with was Dr. Stephanie Leonard, who specializes in food allergies, and has a peanut allergy herself (one of the many cool things she’s involved in is a research study about de-sensitizing kids to peanuts). She was incredibly patient, giving me the chance to ask years’ worth of allergy questions. It turns out items like peanuts, peas, and lentils are more closely related in their antigenicity than their classification taxonomy, a factoid that finally explains my off-limits list

As allergy kindred spirits, we talked about some of our recent dining mishaps. I told her the story of my first week in San Diego, innocently admitting that I have never used my EpiPen, only diphenhydramine. Her subsequent scolding was swift and culminated in me getting four new EpiPens (actually a different type of epinephrine autoinjector, but same idea).


Back home and throwing up several more times in the bathroom, I heard Dr. Leonard scolding me in my mind. Already flushed with shame from ruining dinner (and, I suppose, that whole anaphylaxis thing), I found an EpiPen. Ever the scientist, I did use one that was three years expired. Jabbed it into my thigh…click…count ten seconds…withdraw. I noticed that somehow I had managed to bend the needle while it was in my leg. A drop of blood pooled from the injection site as I waited. It grew larger and began to run. And, miraculously, my symptoms started to subside: the constricting airway, vomiting, cramping, and prickling of early hives all faded away. 

About ninety minutes later, we got Wendy’s.


Note: Type 1 hypersensitivity is an immune system response that involves an immediate allergic reaction provoked by exposure to a specific antigen, such as a peanut. It’s also the process involved in milder allergies, like hay fever.