- i have seen benadryl-based antihystamines powerfully repurposed between internal and external uses with great success in emergencies.

- I have seen people crippled by allergies to things that are absolutely everywhere, and driven homeless, injured, and insane by this.

- I have always been able to manage my allergies with careful and gentle management of exposure and willpower, to make them go away.  Including poison ivy.  I have not met many other people to say this.  I also observe our medical culture to discourage trying it.  I am not myself interested in protective chemicals -- I would rather have the freedom to pursue gentle exposure, when the situation is not dangerous.

- I am not asking others to go outdoors, or expose themselves to unpleasant things.