Facts not to be sneezed at

Myths about allergies are almost as widespread as the allergies

You sneeze when a cat walks by, wheeze through the spring and summer, and can't even get close to a Christmas tree. You may think you're already aware of everything there is to know about allergies and the allergens that trigger them. You may actually "know" much less than you think.

Misconceptions about allergies and what causes an attack are nearly as widespread as allergies themselves. Here are five common myths about allergy triggers and the facts behind them.

Myth No 1:
Allergies may go away.

Fact: This may be correct. It's true that allergies can fluctuate with the season as allergens, like pollen or mould spores, wax and wane. And some food allergies seem to disappear as children grow older -- with the exception of peanut and tree nut allergies, which largely continue into adulthood. But the underlying cause of any allergy is an over-reaction by a sensitive immune system that perceives the allergen as a threat. Over time, your immune system may grow accustomed to an allergen and no longer react as strongly. Or, some other type of allergen may emerge as a trigger. People can develop allergies later in life, even if they never had them as children or young adults.

Myth No 2
Houseplants give off pollens that cause allergies.

Fact: Pollen is definitely an allergy trigger for many people. But the types of pollen that cause sneezing, coughing and itchy, watery eyes are typically from outdoor sources like trees, weeds and grass -- not indoor plants. An extensive study by Nasa found houseplants can actually improve indoor air quality. They act as natural air filters by removing carbon dioxide and contaminants, and emitting fresh, clean oxygen.

Myth No 3
People with allergies shouldn't have carpeting in their homes.

Fact: Not one scientific study affirms a link between the increase of allergies and asthma and the widespread use of carpet in homes. In fact, several studies not only refute a correlation, they even seem to indicate carpet may actually be beneficial to allergy sufferers. A Swedish study found that when carpet use in that country declined by 70 per cent, allergies increased by 30 per cent.

Another study, encompassing nearly 20,000 people in 18 different countries, found reduced asthma symptoms among people with carpeted bedrooms. Finally, a study of more than 4600 New Jersey children found that kids with moderate to severe asthma who had carpet in their bedrooms missed fewer school days and had less need for asthma medication.

"One explanation could be that carpet acts like a filter, trapping allergens and keeping them out of the air so they can be removed through proper cleaning," says Joe Yarbrough of the Carpet & Rug Institute (CRI). "Effectively cleaned carpet can maintain indoor air quality, making it a viable choice for families impacted by allergies and asthma."

Myth No 4
All you need is a vacuum cleaner with a Hepa filter.

Fact: Actually, it's how frequently and effectively you vacuum. To effectively remove allergens, a vacuum must not only be able to pick up allergens, but also keep them contained inside the bag or canister until you can safely dispose of the dirt. Vacuums that expel dust and other allergens through the exhaust are simply putting all those allergy triggers back into the air you breathe. The CRI tests vacuums for effectiveness and green qualities, and awards a seal of approval to those that meet its testing standards.

Myth No 5
Dog/cat hair causes allergies.

Fact: If hair were the source of pet allergies, simply shaving your pet would eliminate your allergy trigger.

In fact, allergies are triggered by proteins in oil gland secretions that get shed as dander, and proteins in saliva that get spread when a pet licks its fur, according to America's National Institute of Environmental Health Sciences. Cat dander is the most common pet-related allergy, but dog dander and rodent urine can also be triggers.

Getting rid of your pet won't rid your home of pet dander and hair. the National Institute of Health reports that both are present in virtually every home. You can mitigate your exposure and reaction by keeping pets off your bed and washing their bedding weekly in hot water, using a prescription or over-the-counter allergy medication for symptoms, and regularly cleaning carpets.