Scabs/bilsters

[Horse Guy]

Been riding a 5YO Appendix pretty much everyday for a couple of months. Not longs sessions, but been riding him everyday.
Yesterday I noticed that on his rump between his hind legs he has one really bad scab thats about an inch in diameter and several smaller ones in the same area.
What caused this? Putting him away wet? Not hosing the lather off?
TBs seem to be more finicky. Example this spring his sheath got infected because I wasnt cleaning it out regular.
He scabed up like this earlier in the spring. I just gave him time off and after he recovered I hosed him off everytime after I rode him but this summer I( got out of the habit of hosing him off because well I had other horses to get rode and I didnt really have the time. Well if I took the time then it meant less time to ride the other colts.
Anyway any of you ever heard tell of this happening on a horse?
Im wondering if an anti bacterial; soap would help him heal faster?
It looks painful.

 

[turn&burn92]

It might have been sweat blisters that have popped and scabbed over. I've heard it's pretty common to get sweat blisters in that area. But I might be wrong I have only heard of this kind of thing a few times. How long has he had it? :?:

 

[Horse Guy]

Its actually a bacterial skin infection. Im treating him with antibacterial soap<hibitane) and hibitane ointment.
Guess this horse will have to be hosed off after I ride him to prevent this from happening again.
This same horse had his sheath infected this spring because I wasnt cleaning it enough.
Vet says some TBs are just prone to this kind of stuff. Have to keep them clean.