Hi Beth,
It's nice to see you using the site. I hope our advice proves useful, as herbal medicine can be extremely rewarding in practice.
Inflammation from a Chinese medical perspective is often diagnosed as Damp Heat. Features of your dog consistent with this diagnosis include the growths, vaginal discharge, and colitis. Basically, exudates, mucous and growths were labeled 'Damp', and the association of these with signs of inflammation and redness gives us the 'Heat'.
Si Miao San (Four Marvels Powder) is our quintessential anti-Damp Heat anti-inflammatory formula. In fact, the formula was developed to treat joint inflammation and vaginal discharge, both of which your dog possesses.
So it seems the place to start. I'd give about 1/3 tsp BID per 20 lbs or so. You can bump up the dose if it is working, but not quite complete in its effect. We've also found that diet (as predicted by Chinese medical theories on the origin of Damp) plays a big role in inflammation and IMPA. In particular, a low carb higher protein diet. An ideal diet would be, at the least, a home-cooked grain free diet. At best it would be raw, although I don't know how you feel about raw diets. If SMS aids, then these diets should be given serious consideration, in order to maximize benefits.
Hopefully you'll see some of that pain decreasing after the diet and herbs have been in place for a couple of weeks.
As for allergic dermatitis, there are about a half dozen formulas we choose from that are all quite different. They include Si Miao San, San Ren Tang (Three Seeds Decoction), Si Wu Xiao Feng Yin (Four Materials Eliminate Wind Powder), and Qing Ying Tang (Clear the Nutritive Decoction). In addition, there are two not yet on the site that you can get from us: Chu Shi Wei Ling Tang, a spin on Wei Ling Tang (Harmonize the Stomach with Five Herbs and Poria), and modified Long Dan Xie Gan Tang (modified Gentian Combination). You can start looking these up on the site to get an idea of what the patients might look like, even buy a couple of bottles of the first four. But we're happy to also guide you on a case-by-case basis for a while as you get going. There are several cases on dermatitis in this forum that will serve as a place to start in terms of learning their essential features.
In conclusion, it's great to be hearing from you, Beth. I hope you find the above advice and the tools on this site useful, so that your experiences in herbal medicine are rewarding.
All the best,
Steve