About Asthma & allergies
An allergic response may vary by person and by allergen. In some cases, the immune response causes the airways to swell and overproduce mucus.
Allergic asthma is a breathing condition where the airways you breathe through tighten when you inhale an allergen. Common allergens include pollen, dander and mold spores. This type of asthma is very common in both children and adults.
The same substances that trigger your hay fever (allergic rhinitis) symptoms, such as pollen, dust mites and pet dander, may also cause asthma signs.