Buttercup Rash

These few days of gloriously hot weather have brought a problem with them. A couple of days ago I saw that Red's legs had suddenly flared up into what looked like a very bad case of mud fever. He is an appaloosa, with pink skin on his muzzle, so I do sometimes have to apply a bit of sun cream on his nose ( which he hates), and it would seem that the very strong sun combined with the buttercups being out has resulted in a bad case of buttercup rash. I had only encountered this on pink muzzles before, but this time Red's legs were covered in crusty scabs from the knees down, and his pasterns were particularly bad.
So, what to do?
I couldn't find a great deal of information about this, so I've gone for some common sense treatment. First, I brought him in and thoroughly washed his legs with hibiscrub (anti microbial), as the scabs were weepy, very much like mud fever or greasy heel spots. This took nearly an hour to do each leg, but, surprisingly, he didn't seem to mind at all. Usually he fidgets when having something done, but he almost seemed to be enjoying this. Then, after thoroughly rinsing them, I left him in the barn for the rest of the day, away from the sun, as, if I am correct, buttercup rash is due to photo sensitisation of the skin.

By the evening, it was time to turn him out. He is already in the field with the least buttercups, but it is impossible to remove him from them entirely. I had intended to put Aloe vera gel on his legs when they were dry, but actually, the skin felt so soft, and there was no sign of new 'weeping' from the rash, that I changed my mind. Instead, I put brushing boots on all four legs to protect them from the sun, and the buttercup pollen, and barrier cream on the exposed bits of his pasterns.

So, the plan is to keep him out of the bright sun while the buttercups are out, and I am hoping this will solve the problem. Still, if anyone has any other experience of this, I'd be glad to hear what has worked for you!