Do allergies cause asthma? The answer to that question is: yes and no.

People are more likely to have asthma if they have the kinds of allergies that affect the nose and eyes, causing problems like a runny nose or red, itchy eyes.

Whatever causes an allergic reaction — like pollen — can also trigger asthma symptoms in some people. But not everyone who has allergies develops asthma. And not all cases of asthma are related to allergies.

How Do Allergies Make Asthma Worse?

Lots of people with asthma find it gets worse when they're around allergens (the things that give them an allergic reaction). Common allergens include dust mites, mold, pollen, and animal dander.

If you have allergies, your immune system reacts to an allergen like it's an unwanted invader. To fight it off, the immune system produces an antibody called immunoglobulin E (IgE).

When the IgE combines with the allergen, it starts a process to release substances designed to protect the body. One of these is histamine. Histamine causes allergic reactions that can affect the eyes, nose, throat, skin, and lungs.

When the airways in the lungs are affected, it can bring on symptoms of asthma (like coughing, wheezing, or trouble breathing).

The body remembers this reaction. Each time the allergen comes into contact with the body, the same thing can happen. Because of that, allergies can make it difficult for some people to keep their asthma under control.

How Do Allergies Affect Asthma?

If you have asthma, it's a good idea to find out if allergies may be causing problems for you. See your health care provider, who may suggest a visit to an allergist so you can find out if you're allergic to anything.

If you have allergies, it doesn't mean that they're causing your asthma symptoms. But knowing what they are lets you and your doctor start looking into the connection.

Limiting your exposure to possible allergens may be a big help in controlling your asthma. If you can't completely limit your exposure to something you're allergic to, your doctor may recommend medicine or allergy shots.