Allergens are substances that cause the body to produce an allergic reaction. When you have allergies, your body mistakenly reacts to specific substances it detects as dangerous (allergens) by making antibodies to fight them. Allergic reactions are symptoms that result from your body creating these antibodies.
Allergens can be airborne or can arise from contact with your skin, from medications, or from food. Depending on the type, they may enter your body through your respiratory system, skin, or digestive tract.
This article explains types of allergens, how they work, and their risks. It also covers how to diagnose allergies and treat exposure to allergens.
When you develop an allergic reaction to a substance, your body treats that substance (allergen) as a germ, or threat. Your body then produces an immune response against the allergen. Instead of producing a healthy immune response, it creates IgE antibodies against the allergens.
If you have allergies, your body begins making antibodies when you expose it to an allergen. Those antibodies attach to specific cells in your body. In the future, when you come into contact with the same allergen, those cells release histamines, which produce symptoms like sneezing, itching, and watery eyes.
Allergies are prevalent. In fact, according to the Allergy and Asthma Foundation of America:
The reason some people but not others develop allergies in response to specific allergens isn't fully understood, but allergies tend to run in families.
Different types of allergens affect people in different ways. For example, some cause respiratory symptoms, while others result in skin rashes or gastrointestinal upset. Less frequently, they can also cause a life-threatening allergic reaction.
Airborne allergens are those that you breathe into your respiratory system. Seasonal allergies and hay fever fall under this category. These types of allergies usually result in nasal allergy symptoms (allergic rhinitis) and/or eye symptoms (allergic conjunctivitis).
Common airborne allergens are:
Skin rashes are a typical response after allergens come into contact with your skin. These allergies are known as allergic contact dermatitis. Common allergens in this category include:
Although it's possible to be allergic to any food, some foods are more common allergens than others. The Food Allergy Safety, Treatment, Education, and Research (FASTER) Act of 2021 identifies the following eight foods as major food allergens:
Exposure to allergens can result in a wide variety of symptoms. Pollen and other airborne allergies most commonly result in nasal and respiratory symptoms, while contact dermatitis often shows up as a skin rash. However, any allergen can cause any allergic symptoms.
Common allergy symptoms include:
Less commonly, an allergen can produce a severe allergic reaction called anaphylaxis. This life-threatening reaction causes swelling in the throat and difficulty breathing. Onset is short—usually five to 30 minutes from exposure to an allergen.
Anaphylaxis is a medical emergency that requires immediate attention. Epinephrine is necessary to treat anaphylaxis. If you have a history of this severe reaction, your healthcare provider will usually prescribe this drug for you to keep at home (called an EpiPen).
Most of the time, allergens are a nuisance. However, exposure to them can result in more serious complications. Some risks of allergen exposure are:
There is a wide variety of treatment options for exposure to allergens. The best treatment is to avoid the allergen. However, sometimes that's not possible or reasonable. Typical allergy treatments include:
When you have allergies, your body mistakenly reacts to specific allergens as dangerous substances by making antibodies to fight them. Allergic reactions are symptoms that result from your body creating these antibodies. Allergies are common, affecting more than 50 million Americans.
Types of allergens include those that are airborne or those that arise from contact with your skin, from food, and from medications. Common allergy symptoms include runny nose, congestion, cough, and sneezing, among others. Less commonly, an allergen can produce a severe allergic reaction called anaphylaxis.
Allergy treatment involves avoiding the allergen and over-the-counter (OTC) medications. If you're unsure what's causing your allergies, speak with a healthcare provider. They can better assist you in determining what you're allergic to.
If you have allergies, avoid allergens as much as possible. Sometimes identifying which substances cause reactions is straightforward. For example, if after you pet a cat you immediately get itchy eyes and start sneezing, you are likely to be allergic to a cat's saliva, urine, or skin cells. Other times, it can be more challenging to determine what the culprit is that's causing your symptoms.
An allergist can help you pinpoint which allergens are causing you trouble by performing an allergy test. They can also help you figure out the best way to manage your allergy symptoms.