Severe urticaria/hives - Danilon?

[Wagtail]

My horse has come out all over in severe hives. The only thing I've changed in the last 10 days is putting him on a sachet a day of danilon and also gradually changed his cubes from Spillers to Dodson and Horrell. Any ideas? I have now on the advice of a vet, put him on some piriton. Upped the dose from 6 tablets to 9 after it made little difference yesterday.

 

[clairelouisehorses]

I have recently brought a pony that is allergic to Dodson and horrell food, his old owners told me he came out is massive hives, maybe worth changing back to see if there is any change

 

[Wagtail]

I have recently brought a pony that is allergic to Dodson and horrell food, his old owners told me he came out is massive hives, maybe worth changing back to see if there is any change

Thank you! He has had danilon before with no ill effects but never dodson and horrell food. I will remove both and if he gets better then reintroduce the danilon. I am supposed to be doing a danilon test to see if his ridden problems improve, but at the moment can't ride him because of the hives!