Allergy

If you or someone you care for has asthma, you know that the disease can fluctuate in severity and the types of symptoms that it produces over time. Asthma can occur in the very small bronchial tubes, which may cause you to have shortness of breath and a sensation of tightness in the chest or a sensation that you can’t get enough air in.  If asthma involves the intermediate size bronchial tubes then you get a lot of cough and wheeze.  If the main problem is in the upper part of the airway (the trachea) then you get mainly a cough without necessarily wheezing or chest tightness.  Most people have a combination of all of the above symptoms during an asthma attack.

Asthma can start at any time of life and its overall course can be very unpredictable.  As mentioned above, a severe viral infection or pneumonia can be the initial event that starts a more chronic form of asthma.  Another common initiating event in more chronic asthma is a change in the environment with an increase in the allergen levels.  This is seen if a person gets a cat to which s/he is allergic or starts a job where the work environment contains high levels of allergen. 

The allergy specialists at Tufts Medical Center are dedicated to defining your asthma triggers so that they can be eliminated or reduced. The most common way that we evaluate you for allergic triggers is by using skin testing. We also look at the pattern that your asthma exhibits and try to deduce any other triggers that may be causing it. 

Triggers involved in short term fluctuations in asthma over the course of a day

Allergens - These are protein substances that float in the air on microscopic (non-visible) particles.  If you inhale a large dose of an allergen to which you are allergic (like animal dander or dust), you will get an asthmatic response that usually peaks within a half hour and then tends to get better over the next several hours if the exposure stops.  This is called the “early phase” response.  Some people also get a delayed response that peaks at 6 to 12 hours.  This is more gradual in onset and in some people can be the predominant reaction.  A common example of this kind of reaction is when a person is exposed to a cat while visiting friends for an evening and then has the major amount of asthma that night.  Much smaller doses of allergen that are inhaled constantly every day can produce a much more chronic form of asthma that is difficult to relate to the cause.

Irritants - These include non-particulate factors such as volatile odors, cold air and irritant particles such as smoke and dusts like fiberglass.  Irritants cause an asthmatic reaction very quickly (usually within a minute). If the irritant is removed there is improvement very quickly within 5-10 minutes.  Some doctors call asthma caused by irritants “reactive airway disease.”  The sensitivity of the lungs to irritants varies a lot over time.  Exposure to allergen makes the lung more sensitive to irritants.

Exercise - Exercise will bring on an asthmatic attack in some people with asthma.  If such a person exercises, the lung function can go from normal to greatly reduced in a matter of 5 to 10 minutes.  Some people with very mild asthma will be able to “run through” the asthma even without treatment.  Some people with chronic asthma and reduced lung function will be short of breath with exercise (without the exercise reducing the lung function). Learn more > (link to exercise asthma page)

Food additives - The most common additive that causes asthma is sulfite that is added to wine and certain foods to prevent spoilage.  Sulfites produce asthma fairly quickly; within 5 minutes usually.  MSG also occasionally aggravates asthma.  Alcohol itself will bring on asthma in certain people who do not metabolize it normally.

Diurnal changes - Regardless of the type of asthma that you have, you may have worse symptoms in the middle of the night.  This pattern is seen in a significant percentage of asthmatics and can be documented by doing peak flow measurements during the night or first thing in the morning and comparing that to measurements made in the late afternoon.   We do not fully understand what causes these diurnal fluctuations, although allergens in your bedding such as dust mites may play a role.  Less common is the effect of regurgitation of acid into the back of the throat at night especially in people who have hiatal hernias of the stomach.  Small droplets of stomach acid are inhaled into the lungs and cause severe irritation.

Triggers involved in longer term fluctuations in asthma over many days and weeks

Viral infections - Certain viruses can cause asthma. The typical pattern is for a person to get an upper respiratory infection that then develops into a cough and then asthma over a period of 4 to 6 days.  Post viral asthma can be very persistent in some people and last for many weeks.  A virus can actually make the lung much more sensitive to the other triggers listed above.  The effects of a virus are very unpredictable and can vary from mild asthma to fairly severe prolonged asthma.  Many people date the onset of their asthma to severe viral infection or a viral pneumonia.  There is as yet no evidence that bacterial infections of the lungs cause asthma.

Sinus Infections - Many physicians believe that a sinus infections makes asthma worse.  While this is somewhat controversial, it seems likely that sinus infections do aggravate asthma in some people.  This is the one instance in which antibiotics might help asthma.

Allergen exposure - There is increasing evidence that inhaling low levels of allergen over a long period of time can cause a more long term worsening of asthma. 

Reflux disease - Acid from the stomach may regurgitate up into the esophagus and during the night especially you may inhale micro droplets of stomach acid into the trachea.  This can contribute to the severity of asthma.

Your doctor will first verify the diagnosis of asthma.  This is important because shortness of breath and wheezing does not automatically mean asthma.  Once a diagnosis is made then treatment can be planned.  Given the complexity of the triggers and natural history of asthma, it may be difficult to determine at any given time what is causing asthma.  The above factors are the basis for planning a long-term strategy for the management of asthma.  Your doctor takes all of the above factors into account when planning what medication you should be on and how you should try to manipulate your environment.

Asthma treatment is more successful if you and your doctor work in a collaborative manner.  Your doctor depends on the input you give with respect to the beneficial and adverse effects of medication.  Peak flow monitoring is often very helpful in determining the effect of medication and exactly what is happening with your asthma over weeks and months.

To make an appointment to meet with one of our expert doctors about your asthma, please call 617-636-5333