Awwww, she is such a pretty girl. She looks like she's posing for that pic. Definitely not rain rot. I also don't believe that's caused by tack. I look forward to hearing what the vet will say once seen in person. I too am thinking parasite or some kind of bite (bug) or sting that got infected. Poor girl. :( Hope you can get to the bottom of it soon (literally). LOL
Have a vet out. Due to this being on the spine the infection could breach into that area (even tho it is open to the outside now). If there is a parasite in there (which there may well be.. I have seen these on cattle, but not to this extent) then the vet will freeze the area and excise the parasite. Only then can healing take place.
If there is no parasite then the wound needs to be debrided and and treated accordingly.
Your horse will likely be given a booster tetanus shot (I would be all over that immediately) and be place on antibiotic therapy (if it is a parasite or not) to help the infection so she can heal.
This is too nice a horse to fool around with that sort of issue in that location.
She should be out today in a couple hours. I feel horrible I didn't get her out sooner but I didn't realize what it was :-\ neither did anyone at the barn. Hopefully she can get it cleared up soon. Will let you know what it turns out to be. Posted via Mobile Device
I talked to the vet about it possibly being from fly larvae or bites etc. She said it could possibly be that. Although doesn't think so because then we would have seen babies & maggots. She's definitely not ruling it out. Yes, she did still think it was a form of rain rot - said she's seen rain rot like that. I could have gotten a sample tested & checked to know for sure but she told me it really wasn't necessary because her antibiotics would take care of a wide range of things.
Wound was cleaned & washed with fungal/surgical type shampoo. Works on a wide range of stuff and I have seen what this shampoo can do - it takes care of EVERYTHING. Will be cleaning every day (like I was before) but now with stuff that's actually going to work on it. Cally has a re-check appointment the following week after to see if there's any improvement. If not onto the next thing & figuring out what it could be.