We’ve all heard allergy myths, although it’s possible we weren’t aware they were myths when we heard them. It’s partly the fault of medical professionals. Some myths come from medical information from years ago that was never corrected, and the internet has a way of keeping bad information around.

Confusion also occurs because allergies are mysterious; no one really knows what makes some people allergic to a particular substance and others allergic to something else. Allergists, however, can debunk the myths, and help people understand the facts.

Here are some of the most common myths, and the facts behind them:

1. Hypoallergenic dogs and cats exist

Sadly, there is no such thing as a truly hypoallergenic dog or cat. Allergens are released in the animals’ dander, saliva and glands—not their fur. Dog allergen levels increase if a dog lives indoors, and are higher in rooms where a dog stays. So if you have a dog and are allergic, keep him out of the bedroom.

2. I have a gluten allergy, so no bread for me

You can have gluten intolerance, but it’s extremely rare to have a true allergy to gluten. If you have an allergic reaction, it’s probably to wheat—not gluten. Many people self-label as having a gluten allergy and avoid gluten without any medical guidance.

3. Egg allergy means no flu vaccine

Egg embryos are used to grow viruses for vaccines such as the flu, yellow fever and rabies shots. Recent research has shown it’s safe for most with an egg allergy to get the flu shot, which can help prevent serious illness. As with any vaccine, anyone administering a flu shot should have procedures in place for the rare instance of anaphylaxis, a life-threatening allergic reaction.

4. Infants shouldn’t be fed highly allergenic foods

For most children, there is no evidence to support avoidance of highly allergenic foods past 4 to 6 months of age. New emerging evidence shows early introduction of highly allergenic foods may promote tolerance.

The abundance of social media in our lives means both good and bad information spreads rapidly and stays around. While this information is easy to access, there are no checks and balances on the internet to ensure that only accurate information is posted.

So, how do you know what to believe and what not to believe? Bottom line: If you think you may have an allergy, see a board-certified allergist for evaluation, testing, diagnosis and treatment. If you do have allergies or asthma, an allergist can create a plan to help you avoid triggers and deal with symptoms.