How to Prevent Allergies

Allergies occur when the immune system overreacts to a foreign substance, known as an allergen, that is ordinarily harmless. Allergies are not always preventable, but there are some things you can do to reduce the risk of developing them.

Common allergens include pollen, mold, dust mites, and certain foods. When people with allergies are exposed to an allergen, the immune system mistakes it for a harmful substance and produces antibodies to fight it. These antibodies stimulate the release of histamines, which leads to allergy symptoms like sneezing, running nose, and itching.

If you already have allergies, taking steps to prevent allergic reactions and reduce symptoms can help improve your quality of life.

Who Is Most at Risk?

Allergies are a common condition that affects people of all ages and backgrounds. More than 50 million Americans have allergies, making it the sixth leading cause of chronic illness in the United States.

Certain risk factors are associated with an increased risk of allergies, including:

• Biological sex: Research studies have found that people assigned female at birth are more likely to develop allergies than people assigned male at birth. Female sex hormones, such as estrogen, are thought to play a role in this increased risk.
• Age: Allergies can develop at any age, but some are more likely to develop at a certain age. For example, most people with seasonal allergies (e.g., hay fever) will develop them before age 20. Food allergies are most common in infants and children, though they can begin at any age.
• Ethnicity: Research shows that certain racial groups are more likely to develop allergies than others. For example, Black and Hispanic children are more likely to have food allergies than White children. In adults, hay fever is more common in Native American and White people than in Black and Hispanic adults.
• Geography: Allergies are more common in urban areas and developed countries. This may be due to increased exposure to allergens and pollutants in these areas and differences in diet and lifestyle.
• Family history: If you have family members with allergies, you are more likely to develop allergies.
• Antibiotics: Some studies suggest that early exposure to antibiotics may increase the risk of developing allergies. Avoiding unnecessary antibiotics may help to reduce the risk of allergies.

Genetics 

Genetics are thought to play a role in the development of allergies, and research suggests that allergies are hereditary. Children with one parent with an allergy are 50% more likely to develop allergies and 75% more likely if both parents have an allergy.

Researchers have discovered genetic variants associated with an increased risk of allergy development. Variations in the gene that regulates filaggrin production—a protein that plays an essential role in the skin’s ability to act as a barrier—have been linked to an increased risk of eczema, hay fever, and food allergies. Similarly, variations in the gene encoding for the protein TSLP (made by certain immune cells) are associated with an increased risk of allergic rhinitis (hay fever) and asthma.

Though genetics play a role in the development of allergies, having a genetic predisposition to allergies does not guarantee you will develop an allergy yourself. Environmental factors also play a role, so even if you have a family history of allergies, avoiding known allergens or pollutants may help prevent allergies.

How to Reduce Risk 

While allergies are not always preventable, there are certain things you can do that may help lower your risk of developing an allergy. 

Allergy Testing

If you suspect you have allergies or are at risk of developing them, ask your healthcare provider for a referral to see an allergist. Allergists are specially trained doctors with expertise in diagnosing and treating allergies and asthma. Your allergist may recommend allergy tests to assess your risk of developing allergies. 

Standard allergy tests include:

• Skin prick test: This test involves placing a small amount of an allergen on the skin and then pricking the skin with a needle. If you are allergic to the allergen, a raised bump (wheal) will appear at the site of the prick. Skin prick tests can identify pollen, mold, pet dander, and certain food allergies.
• Blood test: A blood test called the RAST or ImmunoCAP test measures the level of immunoglobin antibodies (IgE) in the blood, which occur in response to specific allergens. This test is helpful for people who may not respond well to a skin test, such as those with eczema.
• Patch test: This test involves applying small amounts of an allergen to a patch applied to the skin for 48 hours. The patch test helps identify contact allergies that can lead to a skin rash, such as an allergy to a specific chemical or metal. 
• Oral food challenge test: This type of test is usually used to confirm a diagnosis of a food allergy. It is done by giving small doses of the suspected allergen and increasing the amount over time to see if symptoms develop.

Some people may experience mild side effects from allergy testing, such as redness, itching, or swelling at the test site. These are usually short-lived and can be treated with antihistamines (drugs used to counteract the release of histamine when you have an allergic reaction) if needed. 

Early Exposure to Allergens 

Some research suggests that early exposure to certain allergens may help prevent the development of food allergies. Parents and caregivers of young children may be advised to introduce a variety of foods to their growing infant to help prevent food allergies. For example, introducing peanuts to babies between 4-11 months of age has reduced the risk of a peanut allergy.

Avoiding Known Allergens

If you know what you are allergic to or have parents or siblings with specific allergies, you can reduce your risk of developing the allergy by avoiding exposure to those allergens. For example, suppose you are at risk of developing an allergy to pollen. In that case, you can reduce your exposure to pollen by staying indoors during peak pollen seasons, keeping windows closed, and wearing a mask when outdoors.

Keeping Your Home Environment Clean 

Allergens such as dust, pet dander, and mold can accumulate in the home, so keeping the environment clean can help to reduce exposure to allergens. There are several ways to keep your home as allergy-free as possible, including:

• Use allergen-impermeable covers on bedding
• Wash bedding in hot water and run it through a hot dryer once a week 
• Keep the humidity level in your home below 50%
• Quit smoking and avoid exposure to secondhand smoke 
• Dust and vacuum at least once a week 
• Don’t let pets go on furniture like your sofa or bed

Breastfeeding

Breastfeeding may help lower the risk of allergies and eczema in breastfed children, according to some studies. However, more research is needed. Researchers aren’t sure of the impact of breastfeeding on allergy prevention or the mechanisms behind its impact on allergy development. Breastfed infants have a lower risk of developing respiratory and other infections, and breastfeeding seems to have a protective effect that helps lower the risk of many diseases later in life.

Immunotherapy 

Allergen immunotherapy is a treatment that involves exposure to small, increasing amounts of an allergen to build up a tolerance and gradually eliminate allergic reactions. It is a long-term treatment that involves getting shots or sublingual tablets to reduce or eliminate allergies. Shots start out weekly and then eventually get to a monthly schedule for three to five years (the standard timeline for a course of therapy) and sublingual tablets are taken daily for as long as you’re on that therapy.

Though immunotherapy is usually recommended for people with existing allergies, it may also help prevent the development of allergies in people at high risk.

Probiotics 

Probiotics may help reduce the risk of developing allergies, particularly in infants and children. Probiotics are beneficial bacteria and yeast that may have health benefits. Yogurt, kefir, and fermented foods (e.g., sauerkraut, pickles) are rich in probiotics. Probiotics can also be consumed as a dietary supplement. Some studies suggest that probiotics may help reduce the risk of allergies, particularly in infants.

Exactly how probiotics help prevent allergies is not fully understood. Probiotics are thought to promote the growth of beneficial bacteria in the gut, helping prevent the overgrowth of bacteria that may contribute to the development of allergies. Probiotics may also help regulate the immune system and reduce allergic inflammation.

Discuss With Your Healthcare Provider

Talk to your healthcare provider about your concerns about developing allergies and ask them about preventive measures you can take. Before implementing any major lifestyle or medical changes, be sure to discuss them with your healthcare provider. 

If you’re symptomatic, it's worth seeing an allergist. Skin testing can also change over time, so you may have to have it redone as you get older.

A Quick Review 

There is no surefire way to prevent allergies, but certain methods and lifestyle habits can help reduce the risk of developing an allergy or allergies. This includes early exposure to allergens such as eating a variety of foods during infancy, avoiding known allergens, keeping your home environment clean, breastfeeding, and allergen-specific immunotherapy. Consult with an allergist or immunologist to develop a personalized action plan to prevent or manage allergies.