What on Earth is wrong with this horse?!

Never thought about that..I have no idea what it is XD

Viewing the photos - there also appears to be edema where the hair is missing.

Has she been checked for cellulitis?

My first thoughts would be a fungus from the mud that is causing the hair loss, and some type of virus/infection/lymes causing the odd lameness... Sorry I can't offer any other help, but good luck!!

Just a FYI (for the people who might be Googling it), there is no S on the end of Lyme. It is Lyme disease not Lymes.

I know it could be the mud causing the hair loss but like I said she started losing it after she had been in a stable for about a week.

That is just mud on her legs where the hair is gone. I didn't want to scrub it off in case it hurt.

But no she was not checked for cellulitis.

Can horses get lime disease anywhere in the world? I just read about it and it seems to only affect certain parts?

I will more than likely get the vet on Wednesday if it does not improve or gets worse.

Hopefully it is just an infection or something so it would not be that serious?

Interesting, it looks like its fairly new to Ireland... Ticked off by danger of Lyme disease - The Irish Times - Tue, Jun 15, 2010

I'd definitely talk to your vet. I'm not sure what types of common threats you have across the pond...

If she has lyme disease won't other horses there have it too? She is in a field with 20 other horses. I know she hangs out with two of those horses the whole time and they seem fine so far.

Can other infections cause lameness?

Yes, infections can cause lameness.

Lyme disease does not spread from horse to horse. Not every horse has to get it.

Could be mud fever or a fungal infection. Whilst these types of things often start on the surface, any small cut or abrasion can allow it to penetrate the surface of the skin. With mud fever, the skin will often crack thus providing a point of entry for bacteria and other nasties. If left untreated some infections can enter the bloodstream and become systemic, something you will need a vet to check out.

I think you may have 2 issues going on and both of them stem from the mud. I think she may have a skin infection and may also be dealing with bruising. I agree with sarahver. I also would ask the vet about dosing her with some Dexamethasone (Azium) for the swelling in her legs and skin irritation…she may or may not have an infection, but she certainly seems to be having a negative reaction to something in her environment. Perhaps it is the combination of both mud and the type of shavings in her stall. Mud and water will cause the hoof to soften, the photos show her standing on very rocky soil, soft hooves and hard rocks = bruising. Personally, I'd call the vet and tell him your concerns about her having a skin infection and then I'd have the farrier out to check for bruising and thrush.

Good luck with your girl!