I'm convinced I've had a spider bite before as well. Was at the park with the kids, came home and my leg was really itchy, rolled up my trouser leg and there was a little purple patch with two dots in the middle. Half an hour later it was a much larger patch and a bit like a swollen lump and literally the itchiest thing I've ever experienced. Woke in the night with my entire lower leg feeling like it was hot/burning
. It was OK by morning though, back to just the really itchy patch, then that faded to nothing within a couple of days.
Google Images of spider bites look a lot like it though. Yuck. Luckily my skin didn't all fall off like some of the pictures
.