Hi
I have histamine intolerance ( not PV connected) and in the past aquagenic pruritis which is PV related.
I've started to take black cumin seed oil ( organic from health food shop) but many places supply - only buy decent quality) and it has made a difference re itching. Prob because it's a natural anti histamine.
Take one teas twice a day, in a tablespoon of warm water and honey.
Just a thought anyway. Suggest you google " why take black cumin seed oil " and read all info. Some rubbish American stuff out there but some interesting info too.
Louise
x