If you think that fall’s sweater weather is to blame for a sudden bout of itchy, red armpits, don’t sell that wool turtleneck just yet. Your deodorant might be the culprit. Dermatologists have long known that the chemicals in your favorite deodorants and antiperspirants can make that tender skin feel like it’s on fire. “That’s because the openings of the hair follicles make this vulnerable part of your body more porous, and the skin rubs together,” explains Adam Friedman, MD, associate professor of dermatology at George Washington School of Medicine and Health Sciences.
Dermatologists say patients usually come in with two complaints: irritation from antiperspirants and allergic reactions from fragrance in deodorants. “Irritation hurts and can occur within an hour. It’s dark red or pink and looks like a sunburn,” says Friedman. “But with allergic dermatitis, it takes a couple of hours for your immune system to respond. You get swelling and intense itching, and you can see fluid weeping,” he explains.