Just some general info from someone with a lot of allergies including to most of our lovely furry friends. The most severe reactions will generally take place within seconds to around 15ish minutes after exposure, these are often the life threatening ones and if you don't have an epipen on hand the person can die within 15 minutes of the start of the reaction. Less severe, but still potentially dangerous, reactions can take place minutes to hours later and sometimes it takes a full day after exposure for symptoms to start and multiple reactions to the same exposure aren't unheard of. Exposure time and amount also makes a difference for example, one strawberry and I have no issues, 10 and I'm not feeling too good. Repeated exposure can make things worse or even cause someone to gain an allergy they didn't have before, rosewood and CA glue are perfect examples of things that do it a lot. It's not just semen that you have to worry about, dander, urine and saliva are also major sources of reactions to animals. To top all of that off, you don't have to be allergic to that thing to have a reaction from it, sometimes two unrelated things can combine and cause a reaction. A skin test for general dog allergies would be your safest bet for home but the only way to be 100% sure would be to do an allergy panel using blood, sadly they don't do that for animal semen, however a dander, saliva or urine allergy is a pretty good indicator someone would be allergic to the good stuff. From my understanding reason for the blood test is that the the blood test will catch things more reliably and have far fewer false positives or false negatives than doing a skin test. Allergy symptoms can be really weird too, blurred vision, feeling dizzy or light headed, brain fog, pain in odd places, and can even make you feel anxious or nervous out of nowhere and have been known to cause mood swings, rather unfun stomach related things, and that's just to name a few.
