What Is Contact Dermatitis, and Do You Have It?

Two doctors break down everything you need to know.

It started as just one small, itchy patch on my face. I applied some hydrocortisone cream, covered it with makeup, and continued as per usual. By the end of the day, that single spot had become several spots. Still thinking it was a minor allergic reaction to something that could be easily fixed with the application of hydrocortisone, I slathered a thick layer over the spots and went to sleep. But it wasn’t a minor allergic reaction: By the time I woke up in the morning, my entire face was red and swollen like a giant, itchy, red hive, hot to the touch, and impossible to ignore or hide with makeup.

What is contact dermatitis?

Allergic contact dermatitis, often referred to simply as contact dermatitis, is something that can happen to anyone. For me, it happened after I’d spent the better part of that week applying a slew of new skincare products to my face—among them a BHA peel, a retinoid serum, and niacinamide serum—each of them potentially irritating in and of themselves. Together, they basically assaulted my skin and caused it to blow up.

Rajani Katta, M.D., author of Glow: The Dermatologist’s Guide to a Whole Foods Younger Skin Diet and a clinical faculty member at both Baylor College of Medicine and McGovern Medical School at UT Health, says that contact dermatitis is a type of delayed allergy related to something that comes in contact with your skin. “Put a product on, and the rash won’t show up [until] two or three days later,” she says. “Once it’s there, it can last for weeks if you don’t treat it.”

What causes contact dermatitis?

It doesn’t have to be a new product to develop an allergy to it either, says Dr. Katta. “You can become allergic to a product even if you’ve been using it for years at a time,” she says. “Hair dyes are a big cause of contact dermatitis, but it could also be makeup, a moisturizer.”

Other common skin irritants include bandage adhesives and additives in common antibacterial ointments like Neosporin or bacitracin. Dr. Jodi Markus, a Mohs surgeon at Skin Surgery Center in Seattle, Washington, says, “Typically what I will see—post-procedure, after a biopsy or skin surgery—is a lot of itching, redness, and swelling in the shape of the Band-Aid.” “With enough repeated exposure,” she says, “I’ve seen it become systemic, with red itchy bumps all over the body.”

How to treat contact dermatitis:

Dr. Markus advises cleaning the itchy area with soap and water to get rid of whatever irritant might be causing the reaction. “If it’s very mild, you start to see improvement in a day or two,” she says, “but it can take days to weeks to get fully back to normal, depending on the severity of the condition.” She might also prescribe an antihistamine and/or oral or topical steroids to reduce the inflammation.

For those experiencing persistent contact dermatitis needing a referral, Dr. Katta sets the following expectation: “Once your skin gets inflamed, it can take eight weeks for it to calm down. If you’re lucky, it’s not the full eight weeks, but I usually tell my patients to plan on eight weeks.”

To treat it, she explains, “I ask how long has it been going on for, what products the patient is using; then we try to figure out what might have triggered the contact dermatitis and eliminate that.”

To pinpoint the exact ingredient that’s causing the allergy, Dr. Katta conducts skin patch testing, applying tiny amounts of the chemical to the back on patches, which stay on for 48 hours. “Once I know what the patient is allergic to,” she says, “I design a skincare regimen.”

And before you think about self-treating: Don’t do it. “Patients often use alcohol wipes, witch hazel, tea tree oil, essential oils, which are skin irritants that can exacerbate the problem,” Dr. Katta says. “Don’t ever put tea tree oil on inflamed skin,” she warns.

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