Allergies and asthma are closely related conditions, and many individuals with asthma also have allergies. Allergic asthma is a type of asthma triggered by exposure to allergens such as pollen, dust mites, pet dander, or mold. When a person with allergic asthma is exposed to these allergens, it can lead to inflammation and narrowing of the airways, causing asthma symptoms such as wheezing, coughing, and difficulty breathing.