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. Media for Medical/UIG via Getty Images
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." Sharon Dominick/Getty Images
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." Ray Tamarra/Getty Images
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. Getty Images/Photo Researchers RM
Your bed sheets
Dust mites are microscopic critters that feed on dead flakes of human skin. Their feces carry enzymes that can cause allergic reactions such as sneezing, runny nose and/or itchy, watery eyes.
These delightful insects thrive in warm, moist environments with lots of human DNA. So if you're not washing your sheets once a week in hot water, you're likely allergic to your bedding, says Dr. Susanne Bennett, author of the "The 7-Day Allergy Makeover." Other dust mite feeding grounds include your furniture and your carpet. John Greim/LightRocket via Getty Images
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. Erik Dreyer/Getty Images
People usually find out early on if they're allergic to natural rubber, or latex, because it's found in so many products. They learn to avoid rubber gloves and latex condoms. But even the most cautious patient can forget about rubber they may be touching in their environment. Zirwas has seen patients with dermatitis on their hands from hanging on to escalator railings and on their feet thanks to rubber in their shoes. Ariel Jerozolimski/Bloomberg via Getty Images
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. Amanda Edwards/WireImage/Getty Images
Nickel... in your food
About 15% of Americans are sensitive to nickel. They develop dermatitis when they wear certain jewelry or clothing items. But did you know that nickel in your food can also cause an allergic reaction?
Think about it: nickel is a mineral like iron or calcium, which you've seen listed on nutrition labels. It's common in legumes (beans, peas and nuts) and whole grains. Some people with a nickel allergy may get sick, experience joint pain or feel fatigued after consuming these products over the course of a week or month, Zirwas says. It's not an immediate reaction like other allergies so it can be difficult to diagnose. Betsie Van Der Meer/Getty Images
No one really likes the cold, but a few people are actually allergic to it, according to the Mayo Clinic. "With cold urticaria, exposure to cold temperatures causes redness, itching, swelling and hives on the skin that has been in contact with the cold."
Fun fact: You can also be allergic to hot weather (you've probably heard of a heat rash). Or the sun. Or rain. TIMOTHY CLARY/AFP/Getty Images
In 2009, Dr. Thomas Platts-Mills and his colleague Dr. Scott Commins published their discovery of a new allergy called galactose-alpha-1,3-galactose -- alpha-gal for short. Alpha-gal is essentially a bunch of sugars stuck together in blood. The scientists believed tick bites were causing a reaction that made people allergic to the alpha-gal sugar found in red meat.
People with this allergy report waking up in the middle of the night after eating meat covered in sweat and hives. In 2011, Commins and Platts-Mills published a follow-up study that showed tick bites significantly increase alpha-gal antibodies, possibly making our immune systems sensitive to red meat. David McNew/Getty Images