I do know what the hell my board certified ass is talking about actually. Coal tar has traditionally been used for and in some cases, eczematous processes. Wouldn't ever recommend it as first line. Plenty of other options.
My dad has psoriasis as well, he was never prescribed coal tar. Self medicated. He experimented on himself. I guess thats where i get that part of my brain from haha.
Perhaps I misunderstood you as I thought you said hives were not itchy no? As I have extensive personal experience that they are indeed.
So you want him to take a short acting, sedating antihistamine preworkout? bad choice. Benadryl has its own set side effects.
Maybe it is a bad choice, but it is what most people have immediately on hand and would work. He doesn't have to do it on a work out day either...just as a test to see if it is an allergic reaction when he touches a weight,starts to get sweaty or produces adrenalin.
Solar urticaria is from the sun, all oif these are treated with long acting, nonsedating antihistamines, zyrtec, claritin, allegra to name a few.
I agree, these are good choices, if he needed to take them pre workout all the time or in general life eg;working a physical job. although he hasn't mentioned it occurring during any other physical activity.
Urticaria CAN be pruritic. An "allergy test" is a generic word. Overall they are VERY low yield and is in no way indicated at this time. This is called patch testing where they put a bunch of known allergens on patches and sick them to you for a couple days. If it were a contact allergen the most likely affected sites are where he would have contact with the allergen, not diffuse and hive-like. There is no value in RAST testing either - which is also traditionally used for urticaria and other generalized allergies.
Simply put, he has cholinergic urticaria until proven otherwise.
If one was prone to allergic reactions, I would reason myself that I may have allergies related to other things and I should be tested as a just in case. Thus when my sister-in-law found out that she was allergic to shellfish one day, shes was tested and found to be allergic to 6 other very common things, peanuts for one. Not that I don't trust your opinion, but I could say that I am a plumber(which i am not) and give my opinion on fixing your pipes over the internet. His personal GP as was already suggested SHOULD be consulted.
Better reference and source:
http://emedicine.medscape.com/article/1049978-overview
Good article
cheers.