Mine had such bad 'mudfever' that I got the vet to look at it when he did vaccs. White legs are obviously more prone but not just white ones. I spoke to a farrier and he said it might be 'greasy leg'. His thinking is that there's no point in adding grease to grease so I stopped the pig oil and sulphur which didn't have any effect over several weeks and in fact prevent sth escabs from healing as it forms a barrier (i.e. great for prevention but not cure). I was advised to almost debride the affected patches (used a plastic washing up scrubber and went crazy!) and to get my nails in and make it bleed so the patches would be clean. I then applied rainscald powder with a damp cotton bud and in 3 days, the scabs all came off. Now it's healing (a week later all the red patches and swelling had gone) and it's just a bit scarred, no mudfever or whatever it was. I was amazed at this as I'd been nursing it for weeks and had no improvement. I hear Keratex is great as a barrier once it's gone and if you have any handy relatives with pets outside of the EU, Dermobian is also fab-prescription only. Also had rave reviews about Mudguard feed supplement.
Thanx will be writing everyones surgestions down and will be nagging the vet about it all tomorrow hope he has a spare hour or 4