Intrinsic Vs. Extrinsic Asthmaby Jennifer Mitchell Wilson B.S. Dietetics, Dietitian, Health Professional
As most of you know if you follow my posts, we have twins, and both girls have asthma. Our twins are fraternal and are completely different in looks and in personality. It’s almost comical. So, it stands to reason that between the two of them, they would have completely different triggers for their asthma too. Why make things easy? Right?
There are three different sub-types of asthma. They are: intrinsic, extrinsic, and mixed (a combo of both forms). After extensive allergy testing over the summer, we learned that Twin A has extrinsic (or allergic) asthma and Twin B has mostly the intrinsic form.
While the symptoms of both types of asthma (coughing, wheezing, shortness of breath or rapid breathing and chest tightness) are the same, the triggers are different. So what do the differences mean and how do they correlate to treatment?
Extrinsic (or allergic) asthma
According to the Asthma and Allergy Foundation of America extrinsic (or allergic) asthma is the most common form of asthma. It affects more than half the asthma sufferers, some 10 million patients. In extrinsic asthma, the symptoms are triggered by an allergen: usually an inhaled allergen such as dust mites, dog or cat dander, pollen, or mold.
When someone with extrinsic (or allergic) asthma comes into contact with something they are allergic to, the resulting over-reaction of the immune system produces a substance called IgE. Too much IgE is what triggers airway swelling and an asthma attack.
When our Twin A was tested for allergies, she had quite a few positive results for specific things. That testing helped the doctor to determine that allergies were playing a role in her asthma control. Like our daughter, once you have identified your own personal triggers, find ways to eliminate them to help you better control your asthma. Some triggers are impossible to avoid, so newer treatments such as Xolair injections are showing promise in poorly controlled extrinsic (or allergic) asthma by neutralizing the action of IgE.
Intrinsic asthma is triggered by factors other than true allergic reactions.
Factors including anxiety, stress, exercise, cold air, smoke, upper respiratory viruses and other irritants cause the asthma attack rather than an over-reaction of the immune system. In Twin B, we determined that many of the above issues trigger her asthma as well as her acid reflux disease or GERD. Knowing your triggers can be a little harder with intrinsic asthma because there isn’t a specific test to determine it. That being said, doing a journal of symptoms and things that may have been going on at the time can help you determine your own triggers. Your physician may also examine you for signs of upper respiratory infection if you have an asthma flare up to determine if that needs to be treated in addition to the asthma symptoms.
Mixed or combination of intrinsic and extrinsic asthma
Many people find themselves with a combo of both forms, and triggers coming from both allergic and non-allergic causes. Thankfully, both forms of asthma can usually be well controlled with the current controller medications and rescue inhalers on the market. An Asthma Action Plan developed with your physician can help you to determine what medications you need, when to use them, and when to seek additional or emergency assistance.
Jennifer has a bachelor's degree in dietetics as well as graduate work in public health and nutrition. She has worked with families dealing with digestive disease, asthma, and food allergies for the past 12 years. Jennifer also serves the Board of Directors for Pediatric Adolescent Gastroesophageal Reflux Association (PAGER).