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15 Bad Hygiene Habits That Are Way Worse Than You Thought

For most people, good personal hygiene is just a way of life—though everyone skips a shower, forgets to floss, or sleeps in sheets that are overdue for a good washing. How bad could it be? We asked the experts—and the truth may shock you.

Dental health care clinic. Close-up of young man's hands is holding a toothbrush and placing toothpaste on it.VGstockstudio/Shutterstock

Irregular brushing or flossing your teeth

What would happen if you abandoned your toothbrush and dental floss? “You would first experience swollen, bleeding gums, bad breath, and [you] may develop cavities,” says Natasha Lee, DDS, president of the California Dental Association. Untreated cavities would travel to the nerve, requiring root canals, and debris in your mouth would lead to gum disease, a painless condition that eventually causes your teeth to fall out.

And it gets worse. “There is a growing amount of research that indicates an association between gum disease and other health problems like heart disease and diabetes,” notes Lee. Try these 10 oral hygiene habits for white teeth.

Young man washing face on a blue background.StepStock/Shutterstock

Rarely showering or bathing

“Personal hygiene serves a more important purpose than just keeping body odor at bay,” says skin care expert Janine Frances, CME, LMT. It’s not just gross, in other words: Soap and water can prevent acne, rashes, and life-threatening infections. “Bacteria grows rapidly on the body, and when it has lots of dead skin cells to feed off of, bacteria on your skin can cause, itching, irritation, and inflammation,” says Frances. “If you already have a skin condition, such as eczema, not showering regularly can make it worse.”

Eventually, a condition called dermatitis neglecta would set in if you stop showering completely, says Frances. You’ll notice thick patches of brown plaque on the skin, and they can lead to secondary infections. Luckily, dermatitis neglecta is usually treatable with regular washing. In severe cases, topical medication might be needed to break down the plaque.

Woman applying mascara on eyelashes with makeup brushPigprox/Shutterstock

Going to bed with your makeup on

At the end of a long, exhausting day, it might be tempting to nod off without washing off your makeup. Any makeup artist or skin care professional will tell you this is one of the most egregious hygiene mistakes you can make. “Not washing your face daily can create clogged pores which can not only lead to blackheads and pimples but uneven skin color due to overgrowth of skin cells,” notes Frances. And that’s not all: Neglecting to wash off your mascara, eyeliner, and other eye makeup can do serious damage to your eyes. Makeup harbors bacteria, which can migrate under your eyelids and lead to styes, inflamed follicles on the lash line, and serious skin infections. Untreated, these infections could eventually lead to blindness. Don’t miss these sleep hygiene tips for a good night’s rest.

Top view of unmade bedding sheets and

Infrequently washing your bedding

Laundry is a chore some people try to avoid like the plague—but if you actually do, you’re asking for trouble. And this doesn’t just apply to clothes; bed sheets that haven’t been washed in months (or longer) become a petri dish of bacteria, fungus, dust mites, and more—and it’s going to get worse exponentially, as “bacteria multiply rapidly,” says Frances. In the worst-case scenario, unwashed bed sheets—and pajamas and clothing for that matter—will lead to a staph infection. If a staph infection makes its way into the bloodstream, it can escalate to a more severe condition like septicemia or toxic shock syndrome—which could be fatal.

closeup of young woman looking at herself in the mirror to change her contact lens, holding one corrective eye care product, female face in a blurred backgroundSTUDIO GRAND OUEST/Shutterstock

Leaving your contact lenses in for days

One of the poorest hygiene habits that ophthalmologist and eye surgeon Alan Mendelsohn, MD, has ever seen is the overwearing of contact lenses that are never cleaned properly—or at all. “Wearing a contact lens for a week or longer duration results in an exponential increase in severe eye infections, including corneal ulcers,” says Dr. Mendelsohn, who equates this habit to wearing the same dirty underwear every day.

If the term “corneal ulcer” makes you cringe, it’s for good reason. A corneal ulcer is actually an open sore on the cornea that causes pain, redness, discharge, and blurry vision. Most corneal ulcers can be treated with antibacterial, antifungal, or antiviral eye drops, but in some cases, a cornea transplant is necessary. Don’t miss which personal hygiene habits you can skip—and some you really shouldn’t.

UnderwearHelga Petlya/Shutterstock

Not washing your bras or underwear regularly

You’re courting yeast infections, thrush, and urinary tract infections. Untreated, urinary tract infections can travel to the kidneys and cause sepsis, which can be life-threatening; thrush and yeast infections can cause infertility and internal scarring.

And then there are bras, which most people don’t wash after every wear. Like any unwashed clothes, dirty bras trap oils and bacteria, which will eventually cause acne, rashes, and worse.

Black man shaving his

Sharing your toothbrush, razor, or hairbrush

Sometimes it’s a good thing to be selfish—and personal grooming products are a perfect example of a scenario in which sharing is not necessarily virtuous. For instance, poor oral hygiene habits are bad enough—you certainly don’t need the bacteria from someone else’s mouth infecting yours. And the spread of infections is precisely what can happen if you use someone else’s toothbrush, says the American Dental Association. The consequences of oral infections range from gum disease to potentially fatal conditions like heart disease and diabetes.

And sharing razors isn’t much better, as it can not only spread skin infections like staph, but the practice can transmit viruses like hepatitis and HIV. Sharing hair brushes can put you at risk for lice and skin rashes. Here are 37 “healthy” things you can stop doing right now.

Towel hanging at mirror door in the bathroom.pan_kung/Shutterstock

Reusing towels

It’s common to reuse the same towel after a few showers before tossing it in the laundry. But towels that have been used more than a few times—or have been used once at the gym—should be laundered right away. And they certainly shouldn’t be shared, as they can easily harbor bacteria and bodily secretions.

Sharing sweaty towels is an excellent way to spread dangerous skin conditions and infections, like staph, which can be fatal. Need more reasons not to share towels? How about warts and scabies—or more serious conditions like meningitis, hepatitis, and sexually transmitted infections like chlamydia? Chlamydia is a highly curable condition but left untreated it can cause pelvic inflammatory disease and even infertility.

Beautiful female feet under the showerI.Dr/Shutterstock

Walking barefoot in public showers

They make flip-flops and water shoes for a reason: When sweat, hair, and urine collect on shower floors, they can breed bacteria, fungus, and mold. Walking barefoot is a great way to pick up ringworm, athlete’s foot, and nail fungus, to name a few notoriously difficult-to-treat conditions.

Ringworm, a fungal infection of the skin, responds well to topical antifungals; however, athlete’s foot can be far more persistent. In the worst-case scenario, athlete’s foot can cause a secondary infection that can lead to fevers and complications of the lymphatic system. Getting a toenail fungus infection means you’ll be losing your nails on a regular basis—and it’s tough to beat: Not even oral antifungals meds can reliably cure the condition, which will eventually cause permanent deformity of nails and nail beds. In extreme cases, nails infected with fungus need to be permanently removed. (On that note, is peeing in the shower okay? Find out what the docs say.)

Stainless thermos bottle on a wooden table sprayed with water.Andrew Ivan/Shutterstock

Reusing a water bottle without washing it

Staying hydrated is important, but refilling your disposable plastic water bottle too often or refilling your reusable bottle without washing it thoroughly could be as unhygienic as licking on your dog’s toys. In one test, large amounts of bacteria—including the food-poisoning bug E. coli—were found in squeeze-top and screw-top water bottles. Over time, chemicals that leach from dirty plastic bottles can lead to conditions such as PCOS, endometriosis, and possibly breast cancer.

Women wash the apples in the kitchen.George Rudy/Shutterstock

Not washing your produce

How important is it to rinse those apples you bought from the fruit stand? Pretty darn important. Ingesting the bacteria on unwashed fruits and veggies can give you food poisoning, and consuming the pesticides on some of these foods can raise your risk of serious conditions. Pesticides have been linked to diarrhea and insomnia in mild cases; in severe cases, pesticides can be responsible for conditions like increased heart rate, respiratory illness, loss of reflexes, unconsciousness, and even death. Needless to say, a good scrub is well worth the effort.

Woman puting cosmetic glue on fake eyelashes during makupNick Starichenko/Shutterstock

Not caring properly for eyelash extensions

The most frequent makeup-related reason a patient ends up in Dr. Mendelsohn’s office, he says, is due to eyelash extensions. “There are varying degrees of toxicity when the glues get into the eye.” He confirms that glue in the eye can cause mild to moderate vision impairment, but in the worst-case scenario, the glue can become embedded in the cornea and lead to “keratitis, or inflammation of the cornea, which is acutely painful and usually will not resolve on its own.” Don’t miss the hygiene habits you should never do in public.

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Leaving in tampons too long

The most notorious consequence of not changing your tampon frequently enough is toxic shock syndrome—a potentially life-threatening infection. The symptoms start with fever, vomiting, diarrhea, headaches. Left untreated, it can eventually lead to kidney failure or death. Luckily, it’s very rare. The chances increase if you accidentally forget to remove a tampon completely—in which case surgical removal may be necessary.

The man is washing his hair, he use shampoo.TORWAISTUDIO/Shutterstock

Never washing your hair

There are hair experts who believe that frequent washing and shampooing can damage your hair. What’s even more damaging? Neglecting to wash your hair at all, ever—even with water. First, your scalp will start to smell. Eventually, bacteria will start to collect and clog your hair follicles, which could lead to infection. Build up of oils could cause skin infections, dandruff, and yeast to develop. Eventually, without any washing at all, your hair could stop growing.

Clean UpQuinn Martin/Shutterstock

Using your kitchen sponge for too long

Sponges are notorious germ magnets. It’s easy to lose track of how long you’ve been reusing the same sponge, but you could be making yourself sick with the very thing that should help protect you. A dirty sponge can spread salmonella, E. coli, and Staphylococcus, among other nasty substances. In fact, the average dirty sponge may be even more toxic than your toilet. To avoid food- and sponge-borne diseases, replace them frequently. Now, find out the “healthy” hygiene habits that are actually really bad for you.