You've heard of peanut and pollen allergies, and shampoos that make your skin break out in hives. But almost anything in your environment can be an allergen, says Dr. Matthew Zirwas, a contact dermatitis expert at Ohio State's Wexner Medical Center -- "whether it's something that's very synthetic or man-made... or it's something totally natural like a botanical extract."
Click through the gallery to see 10 things you didn't know you could be allergic to.
A few years ago, Zirwas and his colleagues noticed an influx of patients with rashes on their private parts and mothers with rashes on their hands. A bit of research revealed more companies were using a chemical preservative called methylisothiazolinone, or MI, to replace preservatives such as paraben and formaldehyde in pre-moistened personal hygiene wipes and baby wipes. While MI has been around for decades, putting it into widespread use brought the allergy to chemists' attention.
"There's this science behind trying to predict which chemicals people will become allergic to," Zirwas says. "A lot of it is guesswork."
The lotion you've used forever
You've used it every day for the last 10 years, yet suddenly you're seeing red bumps whenever you apply your favorite cream. It happens, Zirwas says. If you're genetically susceptible to be allergic to a certain chemical, you're playing the lottery every time you use a product that contains it.
"You can use something for years and years and years with no problem at all," he says. But "once you're allergic to it, you'll stay allergic your whole life."
Antibiotic and anti-itch creams
Talk about irony. You've got a bug bite on your leg that itches like crazy, so you dab on an anti-itch cream from the drugstore. The next day, the itch is worse, so you slather on more cream. Turns out you're allergic to the cream; that bug bite is now full-blown dermatitis. Zirwas has seen a similar problem in patients using antibiotic creams to treat small cuts or abrasions. These creams usually contain neomycin, which is a potential allergen.
Plants in your home
Mold is a common household allergen. But while most people make sure to clean the bathroom and check the basement, they forget about their indoor plants, Bennett says. Mold can form on leaves or in overwatered soil, releasing mold spores into the air. If you're allergic to mold, inhaling these spores can lead to trouble breathing, coughing and eye/throat irritation.
To prevent mold from forming in the first place, keep a thin layer of gravel at the bottom of every potted plant to help with drainage, and place plants in well-ventilated areas.
If you're allergic to the acrylic resins found in artificial nails, your manicure may not turn out as well as you had hoped. This allergic reaction can lead to redness and swelling in the nail bed -- and in rare cases cause the nail to fall off.
You can also be allergic to nail strengtheners that use formaldehyde, as well as some of the chemicals in nail glue, tape and gel polish.