There are some instances that lean in specific directions, but there are also several that are kind of just melting pots. For the most part I don’t need to use blocks too frequently, but there are definitely some spaces/users that I find are too hostile that it gets in the way of their intended messaging. But then, that line is going to be different for everybody.
Hives are one of the clearest signs of an allergic reaction. There is basically no normal circumstance where those should occur.
It sounds like there are potentially other factors contributing to your symptoms at home, but the last couple of things happening with dogs in general strongly suggests that you have a dog allergy.
I have to echo other posters here and urge you to see a doctor about testing (if financially viable) and mitigation advice.