“She was routinely rubbing into the mat while sweaty, so the allergen absorbs quickly,” she explains. Other such mystery cases were caused by the sulfites in beer, and for one baker, her severe hand eczema came from daily contact with kneading dough laced with Balsam of Peru, a substance found in ingredients like cinnamon.
Dr. Bordone recently saw a patient with red, swollen eyelids who had swapped all her products with new brands, stopped wearing eye makeup, and pared down her routine to just concealer, but was still reacting. “It turned out it was the rubber in her makeup sponges. She lived with this for over a year before she came in for patch testing and we identified the rubber allergy,” says Dr. Bordone.
What are the most common allergens in beauty products?
Fragrance and preservative ingredients are common triggers in beauty and personal-care products. Methylisothiazolinone, commonly called MI, tops the list, according to Dr. Bordone, along with Paraphenylenediamine (PPD), which is widely used in permanent hair dyes that frequently causes severe allergies. “They can appear all over the body and people don’t often make the connection with their hair dye, because they think that will only manifest on the scalp. However, you can get severe eyelid swelling and a rash all over the body,” says Dr. Lazic Strugar.
Fragrances, both synthetic and natural that include essential oils, can be allergy-inducing. Linalool and limonene are two citrus-derived fragrance compounds that are common culprits. “If patients get skin-care products from Whole Foods and it’s organic, they think it’s not causing their rash, but essential oils are actually very sensitizing,” Dr. Lazic Strugar says.
Allergies to these ingredients aren’t always instant. In fact, people sometimes notice that they develop allergies to a product after months or even years, and struggle to believe they’re now allergic to it after using it reliably for so long. That’s because of a phenomenon called cumulative exposure, which is usually how ACD develops. “It never happens the first time you touch something. Your body needs to see it at least twice to get sensitized to it and then produce this memory immune response every time it sees that chemical,” says Dr. Lazic Strugar.
A very common example of that is the notorious Neosporin allergy. Neosporin, a topical antibiotic, has become a product that some dermatologists have condemned. “Neomycin, the main active ingredient, is very highly sensitizing. It’s commonly used and people tend to overuse it, slathering it on cracked, dry skin, or chapped lips. In those cases, when you’re using it on an already compromised skin barrier, it’s more likely to cause an allergic reaction,” she says. But before you begin to suspect all your beauty products of irritating your skin, check in with your dermatologist or allergist to see if a patch test is right for you.