Skin condition that doesn’t jtch

My Golden Retriever has lost clumps of hair and has red bumps, round spots and scabs on her belly, chest and spine. The spine seems to have white dandruff flecks as well. I’ve been using hydrocortisone cream and gave her a bath today with Pet MD Benzoyl Peroxide Medicated Shampoo. Her coat is very thin. She doesn’t to appear to be licking herself excessively or scratching. I also switched her food to a limited ingredient Venison, but she’s over a year and a half and has never shown signs of food allergies. I am travelling and won’t be home for a few more days but wondering if this could be ringworm or mites? She doesn’t appear to have fleas and takes monthly tick medication. We have another dog and she doesn’t have any sign of this so it doesn’t appear contagious. Again, it’s not itchy and she’s behaving totally normally.  Should I continue what I’m doing? Try Benedryl? I will go to the vet when we return if necessary.