Extreme itching?

Maybe a symptom, maybe not. This happens to me once in a blue moon, and never recently enough that I remember to ask my neuro about it next time I see him. I’m an itchy person in general, lol. Have to dab that little tickle under my nose, a little itch on my back. But THIS always starts with my head — think it’s an innocent head scratch and suddenly my whole scalp ITCHES. Then the back of my neck, down to my knees, jump up to the tops of my shoulders, back of my arms, then down to right underneath my butt cheeks, my knees, abdomen, my *face* (forehead! upper lip!*),* behind my ears, lower back. It’s like my nerves are hypersensitive and I don’t have enough hands to scratch hard enough or long enough to put out the fire. I was in my bedroom which I keep at a toasty 64 degrees 🏝️🤣 so I don’t think it’s heat related. I know that scratching doesn’t help but I’m like a 5 year old in this way. I.CANNOT.STOP. Until I take two Benadryl and the scratching is stopped only by me being knocked out. I wake up fine. I have lived in 4 houses since my diagnosis and this has happened in every one of them, I am allergic to **nothing** (sometimes I get sniffles with the change in seasons but not bad enough to take Zyrtec religiously) — animals, plants, foods, perfumes, meds, everything is A-okay. No changes to my shampoo/soap, detergent. I am a creature of habit ☺️. Has anyone else experienced this? Any ideas? Remedies?