It could but it's very unlikely.
Anyhow it's easy to find out. Stop taking it until the rash goes away. Start taking a very low dose again and if you're really allergic, you will break out in another rash. Not a bad idea to have some benedril on hand in case of a really bad reaction, but as long as you start slow you shoud be OK.
On a side note, I had a similar thing happen to me which I blamed on an antibiotic, but it turned out the hives were actually caused by lyme disease.