I have a rash on my hand - how do I find out what it's from?

New perfume? Washing products? Have you been in the garden and touched something that could cause a rash? Is the rash just on your hand? Sounds like you touched something.

@Mz_Lizzy It’s just on my hand, and just from the part that was at this weird angle on the couch when I passed out on it last night – but I sleep on it all the time without getting rashes. No new plants, cleaning things, pets – yesterday I did almost nothing.

Here’s a “page“http://www.healthy-skincare.com/diagnose-my-skin-rash.html that has a lot of info about different kinds of rashes. Sounds like a contact dermatitis. Could be that something was spilled on the couch (or pets did some business there, or brought in fleas). But it might just be from the rubbing of your hand on that part of the couch. Also, could be dust mites in your couch.

Could something have bitten you? A spider? Something like that? Is it swollen too? I was just thinking about when I had a bee sting and the area around the sting was very itchy and I think there might have been a bit of a red rash.

@Mz_Lizzy Not really swollen, all though there are a couple bumps. A spider could have bitten me, I guess.

Ok, it looks most like heat rash, and that would make sense (or at least, I was passed out and can’t really know if my hand was able to breathe). So I guess it’ll go away (after I’ve accidentally clawed off all the skin).