Ok so I'm freaked out now. Last couple days, usaully at night around 7pm I have broken out in mad crazy hives. This has never happened before. I've been trying to figure out if I ate anything weird or anything I could have gotten on my skin. I thought we had solved the problem and that it was a new showering soap I had been using. Than I got the damn hives again tonight. So I started looking stuff up on the net. I have feeling it just might be the Singulair I've been taking for years now for asthma. So far it;s been good, however I read that one of the side effects is hives and/or rashes. I also take my pill at night before I get the hives. So I'm thinking this just might be it, I;m going to the doc this week, but has anyone ever heard of someone becoming allergic to a medication even after years of using it with no problems?