Allergies and asthma can occur separately or together, depending on your particular case. Asthma and allergies often occur together because they have similar triggers.

Allergies

When your immune system reacts abnormally to an ordinarily harmless substance, you have an allergy. Allergies can occur in response to the environment, medications, or foods. Your allergy symptoms depend on the nature and severity of your allergy. Some of the most common allergies result from exposure to pet dander, pollen, and mold.

Asthma

Asthma is an inflammatory condition that makes it difficult for you to breathe. It causes your airways to shrink because of specific triggers. Most of these triggers are also allergy triggers, such as pet dander, pollen, and mold.