What causes some individuals to be more vulnerable to allergies?

Understanding why some people are allergic to certain things while others aren’t can be complex. For instance, a dog might jump into your lap, and instantly, you start sneezing, with your eyes watering. This forces you to push the dog aside in search of a tissue box. Meanwhile, your friend or neighbor might experience no such reaction.

Why does this happen? Why are some individuals more prone to allergies than others? This article will help you understand why allergies seem to affect some people more than others.

It’s All in the Genes

Allergies are often inherited from your parents. If one parent has allergies, you have about a 50 percent chance of being allergic as well, but if both parents have allergies, your chances increase to 75 to 80 percent.

Tell your friends you're "atopic," which means you’ve inherited the tendency to develop allergies. (And hope that none of them are familiar with Greek, since "atopic" comes from the Greek word for "strange.") But don’t feel odd or isolated. According to the American College of Allergy, Asthma and Immunology (ACAAI), as many as 50 million Americans suffer from asthma, hay fever, or other allergy-related issues.

So, your family’s genes may not be in your favor. Does this guarantee constant sniffles? Not necessarily. Keep in mind, even if you have a 60 percent likelihood of developing allergies, there’s still a 40 percent chance you won’t. This explains why your eyes and nose water when Fido is near, but your brother remains unaffected. In the genetic lottery, he got lucky.

Next, explore the impact of environmental factors on allergies.

This information is provided for educational purposes only. IT IS NOT MEANT TO OFFER MEDICAL ADVICE. The Editors of Consumer Guide (R), Publications International, Ltd., the author, and the publisher do not assume responsibility for any consequences resulting from any treatment, procedure, exercise, dietary change, action, or medication based on the information provided. The publication of this material does not constitute medical practice, and this content is not a substitute for advice from your doctor or other healthcare professional. Before beginning any treatment, always consult your physician or healthcare provider.

Allergies and the Environment

Developing allergies is influenced by more than just genetics. Your allergic reactions depend on when you encounter a substance, how often you’re exposed to it, and the quantity of exposure.

For instance, imagine you have a sensitivity to mold spores. While living alone in a spotless apartment, you may show no allergic symptoms. However, once a roommate moves in with her collection of houseplants, an old mattress, and a humidifier (for her skin), you suddenly find yourself sneezing uncontrollably. What happened? You had some exposure to mold spores without any issues, but when your roommate introduced more mold-filled items, your immune system overreacted.

Your age at the time of exposure plays a key role. Recent research suggests that significant exposure to allergens early in life — before the age of 2 — may actually protect against developing animal allergies and asthma.

Where you live can also impact the severity of your allergies. For example, if you're allergic to the big four — grass, pollen, dust mites, and mold — and you live in the Pacific Northwest, where all these allergens are prevalent nearly year-round, you may experience chronic allergies. Your symptoms may include a constantly dripping nose, sniffles, and a sore throat from postnasal drip, but they won't be extreme — they'll just be persistent. However, if you move to a higher, drier area, where grass thrives but mold spores and dust mites are rarer, your allergies may become more seasonal and intense. You might face a month of uncontrollable sneezing, but then the symptoms will subside. Living with allergies is often about balancing the different types you face.