I finally also got the allergy medicine lore I've been waiting for. DSP said he takes a "Benadryl when he needs it" but otherwise doesn't take any antihistamines.
First of all, Benadryl generally isn't going to be recommended first line for maintenance of seasonal allergies due to the fact that it causes drowsiness, he should be taking Claritin, Allegra, or Zyrtec. In addition, these drugs target H1 receptors and a single dose doesn't nail all of them, so they generally ramp up in effectiveness over a few days as you take them (this is why you take them every day, not just days you feel like more allergies are coming up or whatever).
Basically, his strategy of "do nothing except every once in a while take a Benadryl" is really fucking stupid considering that he bitches about allergies multiple times every single day at this point. By the way, oral antihistamines are sometimes a very effective adjunct therapy for post-nasal drip, I always just kinda assumed he was using them this whole time.
Maybe he'll read this and actually get his shit sorted out

