I'm on vacation, so will have to rely on memory (which may or may not be fuzzy).
On my Facebook page today, I've had a wide ranging conversation with Elysa and Erin that started with the discrimination, bullying, exclusion, and contempt that children with very serious allergies face in school and in society today.
From there, we touched on the possible effects on fantasy novel Vampires if they had the bad taste to
bite a person with allergies. Elysa's thoughts turned to a self-medicated allergy sufferer.
I did some research on the internet, and discovered that it might be very amusing to afflict the Vamp with uncontrollable itching. Unusual levels of histamine can do that, I read (I hasten to add).