My horse's sheath has been very flakey?

Well, the flakiness is simply dry skin. If your horse will let you do it, just pull them off. It's okay, someone has to do it :-) It could be a dirty "sheath area".. don't think I can say the "p" word lol, or even worms, causing him to rub his tail. If the "p" is dirty, not only will it have the flakiness, it could also be gummed up inside the sheath and even in the end of his "p". If so, it does need cleaned and yes, the safest way is to have the vet come out, he may have to sedate him. If he gets s "bean" it is very irritating. A bean is dirt and exudate from under the foreskin, and it can get so bad, the horse will not be able to urinate. I have a gelding that, when I went to give him his six month "good washing", was fine til I checked for beans, and he had a good one, I could only get a little bit which broke off, and would not let me touch him again. I had to have him sedated, and the bean was almost an inch in diameter! I felt terrible, I check him often and it got by me :-(