Anaphylaxis to Oatmeal and Psocid Crisps

Occasionally, a seemingly straightforward history of food-induced anaphylaxis may prove to be misleading.  Both patients and their physicians have a tendency to attribute the cause of an allergic reaction to the most conspicuous ingredient that had been ingested while overlooking less likely causes.  Here, we describe a patient whose history pointed to oatmeal allergy, but skin prick tests to oats and serologic testing for oat-specific IgE were negative. Ultimately, we found that the oatmeal had been contaminated with an allergenic insect, Psocid of the order Psocoptera.