I work at a vet's office, and we see a ton of itchy dogs everyday. Of course every vet has a different opinion about the use of low dose steroid injections, especially the newer ones, but in my experience it is usually the only thing that will help. If you have to get them only a few times a year, then you should never see any ill side effects from them. Florida is basically the worst state for allergies, so I've seen my share of poor puppys these last 7 yrs
A lot of times we will give them a Kenalog injection, a steroid with effects that last usually a few months, to break the itching and inflammation cycle, and then follow up with oral Prednisone like you are doing now. The aloe/oatmeal shampoo is definitely good for soothing it a bit, but it's not going to aid in curing it at all. Dogs can be allergic to pretty much everything that humans can, they just manifest the effects of that in their skin as well as upper respiratory symptoms, like the watery eyes you are seeing. If your baby is getting the little bumps that start to scab up, then he/she may need a cycle of antibiotics as well. Those bumps are usually a secondary bacterial infection. Well, hope all that rambling helps you a little bit, and good luck!!