I have tried various anti-inflammatory/ anti-histamine creams in the past. But I've never found them that effective. Preparation H isn't suitable for vegetarians due to one of the ingredients being Shark Liver Oil.
From my experience, the best defense against mosquito itch is living in Florida -- you rapidly become resistant, and eventually the bites fade within a couple hours. However, this has other downsides.
People can argue about whether shearing a sheep or obtaining shellac is harmful - but I think everyone can agree that there's no way to extract the liver of a shark without killing it.
It's still human dominion over animals. And veganism is still veganism. e.g., don't tell me that "some vegans decide it's OK to wear leather" because they're not "a collective entity" or something like that. Veganism is very much a black & white ethos. There is no acceptable gray area for veganism.