How long after an exposure to an allergen (in my case, a cat) does the histamine response last? In my case, I’d like to know how long taking Benadryl would help after I’ve left the vicinity of the cat, showered, etc.
I’ll have symptoms for at least the next couple of weeks (congested chest, etc.) just due to the one exposure, but I’m pretty sure Benadryl isn’t going to help for long - the question is how long? The allergy produces a histamine response, and an anti-histamine will help counter that, but how long does the response last after the allergen is gone?