Allergic reaction?

I noticed the other night when I went to see Fan that she had what appeared to be little "mud balls" on the inside of her back legs, just to the sides of her udder. They rubbed off somewhat, but not totally. They were quite small, about the size of poppy seeds. She had more of them this afternoon. They were in the area around her udder, all over inside her hind legs, between her butt cheeks, and down the inside of her back legs, down to her hocks. I'm guessing that the 'mud balls' are actually caused by dust settling on what may be an oozing rash!

At first I was worried that it was an allergic reaction to the "Clac" insect repellent that I wipe in that tender area (which I stopped doing about a week ago). I thought that maybe the citronella in it (or something else) was irritating her. But I know for a fact that I don't put it between her butt cheeks or near her vulva, or down inside her back legs. So, now my thoughts are; 1) she's being attacked by bugs suddenly, or 2) she is having an allergic reaction to the burrs that get tangled in her tail. I know how much those little "slivers" that come off the burrs irritate me, so maybe when she swishes her tail the burrs are irritating her tender skin.

The other day Veronica asked me if I regularly check Fanny's udder, because she said that some bugs will lay eggs in the udder. I've always checked her and pick out the crud that collects in there, and her udder seems fine. It's the skin around it that is covered in bumps. It's like a heat rash. She's never had this before. You run your hands down the inside of her back legs and it feels like running your hand down severe goose bumps.

When I would put Clac on her udder area, she'd move away from me. Today I mixed up some water with neem and aloe shampoo and sponged the area. She didn't move away when I did that, so I think it made her feel better. When I was done, I put some soothing wound ointment all over the areas, and again she didn't move away when I did it.

Any ideas?

One of the horses I share with gets something very similar every year but only the one horse gets it = so I would suspect an allergy. Is the rash sore or is it itchy? Usually allergies are more itchy - I should know!

Yikes! Poor Fanny!
Any updates for us? I don't know what could cause this.

The insides of her stifles are almost perfectly back to normal. Same goes for her butt cheeks. There are still some bumps down closer to her hocks. I was talking to my homeopath the other day, who also treats horses, and she agreed with me that it was the burrs causing the trouble. The "rash" can be scratched off. It's all tiny scabs. Fanny doesn't move into my hand when I am scratching her (she will move into my hand if she likes when I am scratching a good spot), nor does she move away, so I don't think it really bothers her at all. I had some tea tree oil that I've been spraying on it, which I think soothes it as well. I've been able to keep the burrs cleaned out often enough, so she doesn't get so burdened with them, and that seems to be helping as well.

Even though the fields have been mowed, there were places that the tractor couldn't go that the horses obviously can, so they are still loaded with burrs The other day it still took me an hour to comb out Fanny's mane and tail!!! I am buying "Cowboy Magic" in bulk now, and can't afford to be doing that into the winter. Veronica keeps saying that because the burrs are biennial, they won't be as bad as this year, but I can see the big leaves of the plant in it's "off" year that is growing all over the place. They'll just replace this year's burrs next year.