If mud fever is cause by a bacterium..

[seeker]

...why cant you just treat it with antibiotics?

OK, I'm no vet but my understanding is that it's not inside the body it's a surface irritation thing with the bacteria on the surface of the skin so giving oral antibiotics that would be distributed via the bloodstream would be inefficient / ineffective. However an antibiotic cream / scrub might help?

Dunno really.

It was my incredibly un horsy mum who said why can't we just used Bactroban cream or something like that, and I had to say I didn't know. It's just ALWAYS hibiscrub and sudocrem!

When I first got my horse he had mud fever really bad and the vet gave me an antibiotic cream that was indicated for mastitis related infections in cows. He said it was the best thing to kill mud fever too. However it was hard work getting it on to the skin surface which is where the bacterium lives - I had to get rid of the crusty scabs first. Not easy when the horse thinks you are going to kill him just by looking at his leg

Well, you have to get the scabs off whatever you're going to put on it - I wonder why we
don't all use the cream your vet gave you. Very odd. It's such a problem round here - very clay-y soil and LOTS of mud. Might ask the vet next time he's up at the yard.

I normally try to go for the prevention route. I tought I had escaped completely this year, but the day the sun came out the horse got a puffy leg and the tell tale scabs. From out of nowhere!

My vet says that taking the scabs off is "old thinking". The best product I've found for mud fever is Barrier Hygiene Heel to Hoof. Wipe the mud off the legs (don't wash!), and gob on the gel every day. It takes about 2 - 3 weeks, but the scabs drop off and the skin underneath is pink and healthy. Then apply the gel every 3 days or so as a preventative.
Mud fever seems to be something that is more prevalent in particular fields or soils. Also, it can be best to avoid washing the legs. I kept a pony on a large livery yard years back. He was the only one without mud fever, and the only one who didn't have his legs hosed every night when he came in. The mud dried on his legs in the stable and was brushed off every morning.