Caesar has had hives that look like peas under the skin all over his back…it was either the food or the soap I had been using....
try bathing him with a non soap soap or hypo soap.
I find Caesar does really well with Natural Balance Duck and Potatoe. The vets say that the fillers in dog food can cause allergies in basenjis because they wouldnt eat it in the wild. The duck and potatoe is no soy, no rice, no wheat and no corn. It is a sensitive type food and doesnt have preservatives either. Check for them online...or at a feed store....
You can try different things like listed above and rule things out instead of paying $$ for an allergy panel screening.
I have also found that a lot of dog treats make Caesar sick and I personally stick with Greenies, Nylabones and the Natural Balance treats....
Benedryl is a great way to calm them down when they go through the hives or throwing up. I buy the childrens chewable and it is dosed out by weight.