Histamine tightens the muscles in the bronchial tubes, and the lining of the lungs and airways swell. This causes a tight, uncomfortable feeling in the chest. The airways narrow, causing a high-pitched, whistling sound that you may hear when your child is having an asthma attack.

Exercise, especially in cold air, is often a trigger for asthma. Asthma that’s set off by physical activity is called exercise-induced asthma. Aspirin can trigger asthma in adults who are sensitive to aspirin. Laughing, crying, or hyperventilating can also trigger asthma, as can tobacco smoke, certain viral infections, and some allergens.

Although outdoor allergens, like pollen, may be triggers, indoor allergens and molds are more likely to be a cause of asthma symptoms. Exposure to dust mites also triggers asthma. Keep indoor humidity as low as possible and use special mattress and pillow covers.

Food allergies rarely cause asthma.

One study found that asthmatic children who ate citrus fruits at least once per week were less likely to wheeze and cough.

Summer sports and those that require about two minutes of intense activity instead of long periods of vigorous exertion present the fewest problems.

Avoid outdoor exercise in cold weather and on high ozone days. Camping or hiking trips during the height of the pollen season are not advisable.

Nightly massage and other relaxation techniques have produced good results.

Cat dander is more likely to trigger attacks.