Something that causes a reaction in your body is called an allergen . Allergens can enter your body in a variety of different ways. When you breathe something in through your nose and mouth. When you eat or drink something that causes an allergic reaction. Nuts, chocolate, seafood, milk Drug induced allergies When you take medications or drugs that you have an allergic reaction to.
Allergies are very common.
Allergies can develop at any age, but teens are at the peak age for developing allergies. You may or may not notice that you are allergic to something the first time you are exposed to it. Sometimes, your body can have an immune response to an allergen, but you won't feel sick. But the next time you are exposed to this same allergen, your body will recognize it and react to it, and this time you'll know, because you will feel the symptoms. This is called an allergic reaction.