What causes asthma?

The causes of asthma are not fully understood. Asthma is probably usually caused by a mixture of hereditary factors (those you are born with) and environmental factors, but how these factors work together is still largely unknown.

Allergens from house dust mites and pets are the most common causes, but many other allergens, such as pollen and moulds, can cause asthma. Some patients with asthma have no obvious allergies.

Many things can start asthma attacks

• Animals with fur
• Cigarette smoke
• Smoke
• Dust in beds and pillows
• Dust from sweeping
• Strong smells and sprays
• Pollen from trees and flowers
• The weather

Also colds and exercise may cause asthma attacks

• colds
• Running, sports and working hard

GINA - Global Initiative for Asthma, www.ginasthma.org