Help - Patch of Fur Missing!

[2BullyMama]

Smalls still continues to get more of these circular spots of no fur. He has about 6 now, the old ones are growing hair back but it's just annoying that more have shown up. He was on 2 different Antibiotics, 1st one didn't work the 2nd one cleared the scabbiness but didn't stop the patches from showing up. I switched his food a couple weeks ago from Zignature grain free lamb to Farmina Natural & Delicious grain free Wild Herring...hoping this will help! I just don't know what is causing these hairless spots which is bothering me and the vet can't seem to put her finger on it. HELP!

Hmm... food change may be it. did you add the probiotic?