What is the difference between and allergy an allergen?

An allergy is a harmful immune system response to a normally harmless substance, called an allergen.

When an allergen enters the body, the immune system produces antibodies to fight it off. These antibodies can then cause various allergic reactions, such as sneezing, a runny nose, watery eyes, and difficulty breathing.

Some common allergens include:

* Dust mites

* Pet dander

* Pollen

* Mold

* Food (such as peanuts, milk, and eggs)

Allergies can be mild or severe, and some can even be life-threatening. If you think you may have an allergy, it is important to see a doctor to get tested and treated.