Symptoms and Causes
Asthma is separated into four categories based on the severity and frequency of a person's symptoms. These categories include mild intermittent, mild persistent, moderate persistent, and severe persistent. Those with mild intermittent asthma may only have occasional episodes and no symptoms at other times. Those with severe persistent asthma may require multiple daily medications to control their condition.
The exact cause of asthma is unknown, but it is a complex interaction of different factors. The underlying problem seems to be the release of inflammatory molecules by cells in the lining of the bronchi in response to various stimulators or triggers. The triggers for asthma attacks will be slightly different for each person. Some of them are as follows:
- Allergens such as pollen, animal allergens (hair, cells), dust/spores, food
- Non-allergic (occupational) allergens such as cleaning agents, hairdressing products, epoxy glues, smoke, chemicals
- Exercise (exercise-induced asthma)
- Stress and strong emotional responses
- Exposure to cold air
- Some medicines such as beta blockers and aspirin
Other lung diseases and conditions such as emphysema and infections can have symptoms similar to asthma, co-exist with asthma, and/or exacerbate asthma. Non-pulmonary conditions such as GERD (gastroesophageal reflux disease, also called acid reflux) can trigger or worsen asthma attacks in some people.