Ouch! Many healing prayers for your horse. He looks like a lot of paints do in the summer. Very photosensitive. The Desitin treatment does work wonders, but you can buy the generic brand and it works as well and is much cheaper. Many types of grasses cause this in horses. Of course, not always the same grass or the same horses!!! That would be too easy. A big culpret, though, is rye grass. Really ups the photosensitivity in most horses. We had to stop planting it for winter cover, just wasn't worth it for my mare. Also when what is called winter grass around here goes to head, the seeds and scratchy tops really send a lot of horses over the top.
My old vet in NM used to tell me to put a litle smear of honey on those spots on their legs. He said that the sulpha in the honey would kill the fungus and keep the air out until it did it's job. Only took a day or two, but you have to wash it off, and dry the skin well (very important to keep the fungus away) because of the flies. I tried it and it worked well. But it is hard to do when their whole leg is covered. But, you might want to keep the honey in mind if you can catch the "rot" when it is a small patch!!
I am glad Ricky is looking better. Good luck!!!
