Rashes often show up unannounced and can be very unsettling. And the causes of rashes are varied as the cures. Here’s what you should do when you develop a rash.
Snap a photo when the rash is at its worst. This can help your doctor diagnose it and decide on the best therapy.
Take note of any recent medications—antibiotics or even ibuprofen. These are common causes of drug rashes.
Don’t overanalyze your diet. Nearly every patient I see attributes her rash to a particular food. But the largest scientific studies on diet and skin have failed to show many compelling links. A few notable exceptions: Food allergies are notorious for causing hives and swelling, shiitake mushrooms can cause distinctive red or brown streaks, and a splash of lime on sun-exposed skin can cause temporary brown discoloration.
Look at your nails. If you have an itchy rash on your eyelids, I am going to be suspicious about your nail polish. Tosylamide/formaldehyde resin, found in many formulas, is a common culprit—contact with it simply from touching or rubbing your eyes can cause a rash. Sally Hansen and Rescue Beauty Lounge nail polishes don’t contain it.
Check out your pants. If you are itchy around your belly button, you are probably allergic to nickel (in the metal snap on your jeans). Tons of jewelry contains hidden nickel. Dimethylglyoxime is an over-the-counter liquid that will temporarily turn metal pink if it contains nickel, which can be a helpful tool.
Know when it’s serious. Rashes can be dangerous or even life-threatening. Signs that should send you to the emergency room: skin pain, unexplained blisters or deep-purple skin lesions, or a rash in addition to fever, facial or lip swelling, or difficulty breathing.
When you’re desperate with an itchy rash, three steps offer relief:
First, rub on a 1 percent hydrocortisone cream twice a day. Any topical steroid (such as hydrocortisone) works better when something occlusive is placed on top: a bandage, an Ace wrap, plastic wrap, or tight-fitting clothing. This ultramild strength is safe even for the face for a week or two (no longer than that if you don’t know the cause of the rash), but don’t put it on acne or stretch marks; it could worsen them. If your rash isn’t improving, see your doctor. Or you can stash a cream containing menthol, such as Sarna lotion or Gold Bond Rapid Relief Anti-Itch Cream, in your fridge. The cold, minty sensation distracts the skin’s nerves to reduce itching. Lastly, consider a Benadryl (diphenhydramine) pill if you scratch in your sleep; my patients do the worst damage at night.
Laurel Naversen Geraghty is a writer and dermatologist in her final year of residency at Stanford University.
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