How is horse when moving? Long relaxed stride or pottery short ones? I would remove horse off grass asap - especially during the day when sugar is highest - until you have a diagnosis.
Agree. Shave affected area. Course of antibiotic from vet coupled with dabbing of neat hibbiscrub several times a day on affected area, using damp sponge. Would not attempt to remove crusty bits, leave them alone and it may heal more quickly.
Our boy had what looked like mud feaver a couple of weeks ago. He doesn't have clipped feathers and I rarely wash his heels. It appeared while the weather was wet and there was quite deep mud around the water trough. Because he is allergic to just about everything under the sun and...