Definitely need to scope. Each horse/case is individual, but in my case, I spent years listening to trainer and vet treating what were clear ulcery symptoms without scoping. We’d throw Nexium at him daily, misoprostol, injectable omeprazole, sucralfate, and supplements. He’d be “better” for a bit only to have symptoms return. Not once did vet recommend scoping and I wasn’t savvy enough at the time to go against vet and trainer and demand anything else.
Moved horse, got new much better vets. After 10K worth of diagnostics and treatment for ulcers, horse has inflammatory bowel disease, causing delayed gastric emptying, causing ulcers. All that nexium, etc not only didn’t treat the issue but caused a dysbiosis in his gut that has taken months to resolve. He ultimately needed steroids and better management with alfalfa hay added.
I cringe now thinking about how poorly treated he had been.