What are the common triggers of asthma?

There are several categories of agents known to cause asthma attacks:

• Environmental agents, such as pests, pets, dusts, pollution, and tobacco smoke
• Respiratory infections, such as the "common cold"
• Climatic conditions, especially cold, dry air
• Sinus infections and chronic sinusitis or post-nasal drip
• Gastroesophageal reflux disease
• Medications, especially aspirin
• Industrial exposures

Which environmental agents are likely to cause asthma attacks?

• Household mites
• Cockroaches
• Second-hand tobacco smoke
• Dogs and cats in the home
• Mold or mildew in the home
• Air pollution in cities, which includes the chemical ozone
• Dusts such as road dust
• Engine exhaust particles
• Grain dust and farm chemical dusts
• Fragrances, household aerosols and cleaning agents

What infections are responsible for triggering asthma attacks?

• The "common cold"
• Influenza ("the flu")
• Ear infections
• Other viral infections, such as bronchitis and sinusitis
• Pneumonia

Why does cold, dry air trigger asthma in some people?

The cold, dry air causes receptors (nerves) in the lung to activate leading to inflammation and constrictions of the airways

Are thunderstorms associated with increases in asthma attacks? Why?

Yes, they are, but it is unknown what about thunderstorms leads to an asthma attack. Some think it may be due to relatively cold air in the storm in addition to stirring up pollens.

My child has had a runny nose, and is now wheezing. Does he have asthma?

• Possibly. However, not all wheezing in children is due to asthma. More often, it's due to a viral infection, such as the common cold or influenza. If so, then it is likely to go away once the child gets better. In some children, an initial episode of wheezing can represent an asthma attack, and the child should be evaluated by a physician.
• Some viral infections in early childhood are even thought to protect children from later developing asthma

Does sinus disease lead to asthma?

• Sinus disease, such as chronic sinusitis or post-nasal drip, can trigger an attach of asthma, but does not cause asthma in people who do not have asthma.
• Treating the sinus disease can lead to decreases in the number of asthma attacks in susceptible people.

How does gastroesophageal reflex disease (GERD) lead to asthma?

• Some people who have asthma will experience triggering of attacks of asthma due to GERD
• GERD is a disease of the upper part of the stomach and esophagus (the "food tube" leading from the mouth to the stomach) where dysfunction of these parts leads to stomach acid going up out of the stomach, into the esophagus
• The acid, once in esophagus, can be disrupted into small particles and become airborne, when it can then be inhaled
• Once inhaled, the acid particles can trigger receptors (nerves) in the airways and set off asthma attacks
• Not all people who have both GERD and asthma will experience asthma attacks
• In some people, treating their GERD with the newer antacid medications will lead to resolution of asthma symptoms

What medications can cause asthma?

In few patients, aspirin will set off asthma.

• Asthma due to aspirin tends to be more severe and is sometimes marketed by nasal or sinus symptoms, which are often more troublesome than the asthma
• Aspirin can lead to asthma even in people who previously took it without any problem
• A few other medications, including a group of blood pressure and heart medications called "beta-blockers," may set off asthma attacks. They do this by activating the nerves that cause constriction of the airways.  Before a doctor prescribes these medications, he or she usually would ask about whether a patient had asthma.
• In some cases, patients receive beta-blockers even though they have asthma but they do not experience asthma attacks.
• In other cases, patients who did not know they had asthma, when given beta-blockers, and subsequently have an attack of asthma.  These patients most likely have had mild asthma and the medication triggered symptoms leading to the apparent diagnosis.