Watch What You Touch
Unfortunately, many rashes that fall under the category of allergic or irritant contact dermatitis can look like any other more serious rash, making it difficult to diagnose [source: Cleveland Clinic].
You have to take a moment to consider any new chemical product you've tried, if you're allergic to some type of metal you're wearing or a rubber product you've come into contact with.
If you've been outdoors, consider you may have come into contact with poison oak or poison ivy. If so, oatmeal baths, cold compresses or over-the-counter medicines can help reduce the itching and inflammation while you wait for the rash to pass [source: Mayo Clinic].