Are Allergies Genetic?

Chances are you know someone who struggles with an allergy. In the United States, over 24 million people have been diagnosed with seasonal allergic rhinitis, meaning that they are allergic to pollen coming from grass, trees, and weeds. Over 32 million people in the U.S. have been diagnosed with food allergies, the most common of which are shellfish, milk, and peanuts.

Several risk factors can contribute to the development of allergies—including whether or not it runs in the family.

“The tendency to develop allergies can have a genetic component," explains Samata Kamireddy, MD, assistant professor of medicine at Emory University School of Medicine. "You can’t necessarily pass down a specific allergy, but if mom has lots of environmental allergies, a child can develop some form of allergic disease.”

Ahead, we'll take a look at the potential connection between allergies and genetics, other things that contribute to the development of allergies, and how parents can manage their kids’ allergy symptoms.

The Connection Between Allergies and Genes

Studies have found that there is a correlation between a person’s genetic makeup and their likelihood of developing allergies. If a parent has an allergy, a child is 50% more likely to have one too. With both parents, that child’s likelihood jumps to 75%.

“Allergies to food and environmental allergens are more likely in people who have a family history of allergy," explains Gerald Lee, MD, pediatric allergist/immunologist at Children’s Healthcare of Atlanta. "For example, having a sibling with a peanut allergy increases the risk sevenfold. And identical twins have a 64% concordance in having peanut allergy."

Though some allergies may have a family connection, it’s difficult for doctors to know exactly what percentage of allergies are solely genetic. 

“While we do see that allergies tend to run in some families, there is limited data on the inheritance and genetic causes for these observations at this time," says Kimberly King-Spohn, director of genetics counseling at Wellstar. "We are not typically doing genetic testing in a clinical setting for allergy-related concerns."

Even if genetics make a person predisposed to an allergy, other factors can also shape a person’s allergic response.

What to Know About Genetic Allergies

A person experiences an allergic reaction when the body’s immune system overreacts to an item or substance. The immune system then creates antibodies called Immunoglobulin E (IgE). The antibody transports to cells, which in turn release chemicals. Those chemicals cause an allergic reaction. The process is the same whether allergies have a genetic component or not.

What’s also similar is the fact that allergic reactions can change with age—for better, or worse. “​There is still lots to understand about allergies and their progression.  They can worsen over time and improve over time,” says Dr. Kamireddy.

A variety of factors come into play when determining what course an allergy will take. “Certain [allergies] such as milk, egg, and wheat [can be] outgrown as a child gets older," Dr. Lee notes. "Others, such as peanut or tree nuts, are less likely to be outgrown."

Environmental allergies can also improve or get worse. Research shows that climate change can impact allergies, given that pollen season is starting earlier, lasting longer, and spreading more pollen.

While a cure is not available, allergies can be treated and managed. “Although immunotherapy to peanut can decrease the risk of an allergic reaction, there are current clinical trials investigating whether immunotherapy to foods other than peanut or certain medications can protect children from a food allergy reaction,” notes Dr. Lee.

Allergy shots, antihistamines, and oral medication can also help suppress allergy symptoms and lessen severe reactions.

Other Contributors to Allergy Development

Heredity is just one of many potential risk factors for developing allergies. Sex, race, and age can also play a part in whether a person has an allergic reaction. Living in a heavily polluted area can be a component, as well as smoking, or consuming second-hand smoke. Diet, along with other lifestyle choices, can also play a part.

“For [a] food allergy, certain co-factors such as infections, activity, sleep deprivation, medications like NSAIDs, and alcohol may make reactions more likely if exposed to an allergen,” notes Dr. Lee.

When looking at risks for developing allergies later in life, experts offer possible explanations.

“There are some hypotheses circulating but nothing that is definitive," explains Dr. Kamireddy. "One example is the hygiene hypothesis, which essentially states that we are too clean as a society and because of that, our immune system doesn’t get a chance to develop as well as it could if it was encountering various bacteria and viruses."

Experts note that being armed with information regarding other family members who have allergies, being aware of when you experience allergic reactions, and talking with your healthcare provider about possible risk factors can help you determine the best course of treatment for allergies.

How Are Allergies Diagnosed?

A medical professional can help you determine if an allergy test is needed, along with the best one for your circumstances. There are multiple testing methods available. Skin tests consist of pricking the skin with specific substances, and watching for a reaction. A doctor can also scrape the skin or apply the allergen externally.

A healthcare provider may also perform a blood test and send it off to a laboratory to see if antibodies for the allergen are in the blood. A provocation test means a doctor would apply the allergy substance to trigger a response, such as lining the mucous of the nose with types of pollen.

Some studies have looked at whether genetic testing can help predict food allergies. While there have been strides made in this area, experts note that more research is needed. Presently, there is not a definitive test that can determine if an allergy is hereditary.

How to Make Informed Decisions About Allergies

As a parent, it can be hard to know how to manage a child’s allergies when you aren’t sure what your child is allergic to. The first step is to find out what substances or foods could present a problem for your child. “​If you are suspicious that your child has allergies or if there is a significant family history of allergies, I recommend seeing an allergist to help guide you. There is no good way to manage unknown allergies,” advises Dr. Kamireddy.

Once you are aware of allergies, allergy shots, nasal inhalants, and other medication can help manage the symptoms. In some instances, staying away from the allergen all together will help keep your child healthy.

In the case of an emergency where your child has been exposed to an allergen and is experiencing trouble breathing, swelling, abdominal pain, dizziness, or other concerning reactions, call 911 immediately.

“Making sure you have an epinephrine autoinjector for emergencies is very important for food allergies,” adds Dr. Kamireddy. When dealing with allergic reactions, being as informed and prepared as possible is key.

A Word from Verywell

Knowing your family’s history of allergies can be beneficial to your child. While genetics is not the only factor in the development of allergies, understanding its impact is important. Talking with a healthcare provider and/or pursuing testing with an allergist can help you manage and successfully mitigate severe risk of allergies in your child.