urticaria
"After travelling to Japan in Sep 2015 and having ,enjoying with tremendous quantity of sea food  sasimi, BBQ Wangyu beef and wonderful cheese cake ,  I woke up next morning with hives literally covered  my both front arms outer parts and partially between shoulder and  neck. Never experienced previously with  allergic reaction in my life ( btw I am 52y/o) 
After doing intensive checkup, blood tests, etc., etc.,  and more etc. finally one of the brilliant Doctor gave me the Zyrtec.
I have been taking (one a day) for  2 weeks. 
I still don't know (my doctor either) what triggered these ugly hives but eventually all disappeared and gone to hell. I highly recommend. I agree about   side effects especially causing impair my thinking."