If your jewelry makes your skin break out, wear stainless steel or nickel-free pieces instead. You can't spread a poison-plant rash by scratching the blisters. You can be allergic to perfumes, lotions, and makeup, too. If any of these things brings on a rash, ask your dermatologist to help you track down the cause. Luckily, people with a rubber allergy can wear underwear with spandex, vinyl gloves, and shoes without rubber.
Prickly heat is most common when the weather is hot and humid.
You might find the tiny reddish pimples of prickly heat in the crook of the arm, under your chin, on your chest or back, or on the backs of your knees. The best cure is to stay cool and dry, and avoid clothing that's too tight. Be sure to dry your skin off well after you take a bath or shower. Then, before you dress, sprinkle yourself with a body powder made from cornstarch. Hot weather, exercise, stress, and some foods can cause hives.