Sweating in one spot

My OTTB is sweating in one spot on his right shoulder when facing him. It is wet to the touch, but has only happened once. I read it could be from past trauma and possibly nerve damage. I have ruled out EPM as there are absolutely no signs of it other than the sweating. He is sound, pooping, eating and drinking perfectly fine! I thought maybe it could be his saddle too. He has filled out significantly since I have had him, so possibly pinching? Spoke to saddle fitter this am and she suspects it could be too. Curious to see if anyone knows anything, or past experiences. Thank you!

this type of patch sweating can occur after tissue damage. I have a friend who had a horse that suffered a bad fall on its neck. After that the horse would patch sweat on the neck except when he was very sweaty, then the patch would be dry.

You are very right to suspect that the saddle might be pinching down and causing nerve irritation which shows locally on the shoulder. IF your horses condition has changed, the saddle needs to be checked and reflocked appropriately.

good call

With my mare, it was localised myopathy caused by PSSM : in other words, small patches of tying up here and there on the big muscles. (Vet checked for tying up confirmed after each episodes.)

New diet, new working regiment and it got under control.