Asthma is a disease in which the airways become blocked or narrowed. These effects are usually temporary, but they cause shortness of breath, breathing trouble, and other symptoms. If an asthma episode is severe, a person may need emergency treatment to restore normal breathing.

Allergies are diseases of the immune system that cause an overreaction to substances called "allergens." These substances can trigger sneezing, wheezing, coughing and itching. Allergies are not only bothersome, but many have been linked to a variety of common and serious chronic respiratory illnesses (such as sinusitis and asthma). Additionally, allergic reactions can be severe and even fatal. However, with proper management and patient education, allergic diseases can be controlled, and people with allergies can lead normal and productive lives.