itchy neck when waking up

[shesellsshesellsbytheseashore]

Does anyone have any idea what this could be?? Started itching randomly over my adams apple area about a month ago - never gave it any real thought and it was only when waking up in the morning.

Then one night i woke up in the middle of the night and my entire neck and under my chin was itching like crazy - ended up bright red and it was so sore and hot.

Went back to sleep and woke up in the mornign with the same crazy intense itch which then turned into a bright red neck and really hot and sore. i decided to strip the bed incase it was the washing detergent (that ive used for years) so put it on a 90 wash with non bio washing powder, no fabric softener
Then i put it on again with no detergent so it would be thoroughly rinsed.

Same thing happened the next morning, woke up scratching like mad on my neck and under my chin - so then thought maybe its the pillow.
Went out and bought a hypoallergenic pillow - no difference at all.

Then i bought some allergy blocking pillow covers - no difference at all.

Every single morning without fail im itching and scratching like mad and my whole neck ends up red raw and very hot.
Its not raised, therse no bumps or lumps its just very very red and itchy.

So i then I thought maybe im just dry so used some diprobase, made no difference.
I moistured thoroughout the day and before bed, but made no difference the next morning, tried a different moisturiser, no difference. Tried eurax and that helped a little but says only use twice a day so i use before bed but made no difference to the itch when waking.

I tried 1% hydrocortisone cream which has helped a little but im still itching on and off throughout the day and then the intense itching when i wake up again.

I tried putting a little of the washing detergent on my neck to see if i'd react and nothing - also tried a little shampoo and conditioner neat on my neck and no reaction so i'm guessing its none of that.

So any ideas what else it could be?? Its only my neck, which is very odd, as if i was reacting to something surely the rest of my body would be reacting?