Itchy Pallet can anyone help

Buckfast W

Hey guys first time posting I just hope I'm in the right thread.

Just looking for a bit of advice or help with a problem. My girlfriend has had an itchy pallet for a few weeks now. She's been to the dentist and doctor and they can't seem to find anything wrong (they're going to refer her to a specialist). It's gotten so bad in the last few days that she can't sleep properly as it keeps waking her up.
She has been taking an antihistamine which helped at the start but no has no effect. She tells me that she isn't eating anything new so she's certain that its not an allergy. (But could be)

Has anyone had something similar or could anyone recommend something to help. She's being driven crazy by this.
Thanks