My dal had very similar symptoms. Vets managed to build a $5000 bill before we ran out of options. Turns out it was a simple as a diet issue.
We initially changed him to Royal Canin Hypoallergenic Dry food. The improvement was almost immediate. The bad part about this option is A) it's not cheap and B) it requires a prescription from the vet. Most vets that I called would require a yearly blood test in order to write us new scripts. I guess it was determined that he has "irritable bowel disease" - also known as "we dont know the exact cause". A vet told us about the Hypoallergenic food so changing his diet wasnt advised as a solution but it just happened to work.
After MUCH research royal canin also offers a dalmatian specific dry dog food at a much more affordable price that you can get on chewy & amazon.
My boy has been on it for about 2 years now and we havent had a single skin/bowel issue ever since. Hope this helps!
EDIT: Royal Canin Dalmatian Adult Breed Specific Dry Dog Food, 30 lb. bag https://www.amazon.com/dp/B077Y83V8L/ref=cm_sw_r_cp_apa_i_-8mfEb022EDBC
Royal Canin HP Hypoallergenic Dog Food (25.3 lb) https://www.amazon.com/dp/B004OWRRME/ref=cm_sw_r_cp_apa_i_B-mfEbXQAJXGT