What causes asthma?
The exact cause of asthma isn't known. It's possible that a combination of genetics and environmental exposures interact to cause asthma to develop, most often early in life. Risk factors for developing asthma include:

• Atopy, an inherited tendency to develop allergies
• Certain respiratory infections during childhood
• Contact with airborne allergens
• Exposure to viral infections
• Parents who have asthma

An asthma attack occurs when asthma symptoms become worse than usual. During a severe asthma attack, the airways can close so much that your vital organs do not get enough oxygen. Learn to identify the asthma signs and symptoms here.