The primary symptom of asthma is a noticeable and long-duration constriction of a person's respiratory pathways, which partially suffocates them and renders them incapable of inhaling and exhaling freely. This is a result of inflammation of the bronchial tubes.

Symptoms of asthma can occur on their own, or they can be the result of exposure to air at low temperatures, cigarette smoke, and various other airborne contaminants, infections of the respiratory tract, mental pressure or allergies to food or medication. Tautening of the bronchial muscles occurs, and the inner lining of the bronchial tubes become inflamed, and mucus is produced in greater amounts. Under the effect of asthma, breathing is much more difficult, and is often accompanied by raspy wheezes.

In most cases, the symptoms of asthma are infrequent, and often differ greatly from person to person. Their complexity and durations are highly variable, but are usually temporary, lasting for a few days in most cases. However, in certain very serious cases, they may become chronic unless treated.

Asthmatic reactions can be triggered by many different things, and even that varies widely from person to person. Asthma's random nature is one of the most frustrating things about it, and it faithfully maintains this constant of uncertainty to the letter.