Consider it the worst type of fashion blunder: Your favorite items could be at fault for otherwise-unexplained breakouts and rashes. See how your duds measure up.

METAL AWARENESS: If you've ever noticed an itchy, red rash on your earlobes, the nickel in your everyday earrings could be the culprit; nickel can cause flare-ups in people with metal allergies. Like other skin sensitivities, a nickel allergy can develop over the years, and you should know that this metal can also be found in bra clasps, jeans' buttons, and costume jewelry. But it's easy to beat: You can ban the rash with a simple over-the-counter 1 percent hydrocortisone cream; stick to jewelry made from surgical steel or platinum (both metals are hypoallergenic); or use a nickel-detection kit to test accessories while you're shopping. To be on the supersafe side, switch the metal hooks and buttons on your clothes for plastic or fabric-covered ones. Another good trick is to put clear nail polish or moleskin on the inside of your jeans' buttons. Having a nickel allergy also means you have sensitive skin, so make sure to use hypoallergenic and fragrance-free cosmetics and bath products.

TIGHT SQUEEZE: Denim is a coarse fabric, and the current trend for thigh-hugging skinny jeans can make you sweat and chafe. That leads to clogged pores and ingrown hairs — or leg foliculitis. You'll usually notice it on your thighs, but if you tuck your jeans into boots or forgo underwear, you can get breakouts mid-calf and in the bikini region, too. Hydrate your legs regularly with a non-comedogenic exfoliating moisturizer (ingredients like alpha hydroxy acid are great), and always wear underwear. Use a salicylic acid spot treatment on new ingrowns, and see your dermatologist if they don't heal in three days — she might need to drain them.

EXTRA BAGGAGE: Pack rats, beware! Heavy, oversize purses or travel bags can rub your shirt or bra straps against your shoulders, leading to sweaty, warm patches that are ripe for breakouts. If you have pimples on your upper back or shoulders, you should wash daily with a 10 percent benzoyl peroxide body wash. Opt for tops in breathable, natural fabrics, like cotton and silk, which ventilate better than synthetics; at the gym, wear moisture-wicking shirts to help stop sweat from clogging pores. If the breakouts continue, ask your derm for a prescription for Evoclin foam or an oral antibiotic like doxycycline. In-office treatments like Isolaz lasers and chemical peels can be done at higher intensities for body skin than facial skin and are good for more persistent breakouts, too. And remember to carry your bag on alternate sides: Too much neck and shoulder pressure can lead to long-term back problems.

What Do You Think?