What Is Meant by "Inflammation" in Asthma?
More and more, we hear talk about "inflammation" in asthma. Our view of what asthma is has changed over the past decade or so. No longer is the focus exclusively on narrowing of the breathing passageways (bronchial tubes) due to contraction of the bronchial muscles that surround these tubes. Increasingly, there is emphasis on the importance of inflammation of the bronchial tubes and treatment with medications that reduce this inflammation (anti-inflammatory drugs). This pamphlet discusses what is meant by inflammation in asthma, and why it is so important to treat inflammation in asthma, even if it is not causing us any symptoms, such as cough or wheeze or shortness of breath.
Other Examples of Inflammation
Inflammation is a term used in medicine to describe how the body reacts to various types of injury or irritation or infection. Inflammation takes various forms. A sunburn is a type of inflammation of the skin in reaction to the ultraviolet rays of sunshine. The rash of poison ivy is another kind of inflammation of the skin, an allergic reaction to oils on the leaves of the poison ivy plant.
Inflammation Can be Acute or Chronic
Like these two examples, some types of inflammation last for only a brief while and then go away when the cause of the irritation is removed. However, other types of inflammation can last for months or years or even a lifetime. Still considering inflammation of the skin, psoriasis is an example of a long-lasting or chronic inflammation. Rheumatoid arthritis is a chronic inflammatory disease of the joints of the body.
Whether it is brief (acute) or long-lasting (chronic), inflammation can go away without leaving a trace. Other times, inflammation can leave behind scarring and permanent changes in the body.
During Attacks of Asthma, the Bronchial Tubes Become Acutely Inflamed
It has been known for a long time that acute inflammation of the bronchial tubes occurs during asthma attacks. The bronchial tubes become swollen and narrowed and mucus is secreted into the tubes from glands in the walls of the tubes. Swelling of the tubes and their plugging with mucus make it difficult to breathe. You may cough up some of this thick, gooey mucus during a flare of your asthma.
Asthma is a Chronic Inflammation of the Bronchial Tubes
An important medical discovery several years ago was that some inflammation is present in the bronchial tubes of persons with asthma even when they feel well and when their breathing is normal. The cause of this chronic inflammation is not known, although in many instances it has the appearance of an allergic type of reaction. The inflammation may be mild, so mild that it does not cause narrowing of the bronchial tubes. But the persistent or chronic presence of the inflammation probably is what makes the bronchial tubes capable of narrowing abnormally. The bronchial tubes in asthma are said to be "twitchy" or easily sent into spasm or narrowing. What makes the bronchial tubes "twitchy" or vulnerable to a variety of stimuli in the world around us-whether it be dust or exercise or cat dander or cold air-is thought to be the persistent presence of inflammation in the bronchial tubes.
Ways to Reduce Inflammation in Asthma
We do not yet know how to turn off the inflammation of asthma. There are, however, two principal ways to reduce it. The first is to identify those things that are stimulating the inflammation in the first place and to rid them from the environment, meaning generally from the air that we breathe. Some things, like cigarette smoke and air pollution, are likely to worsen the inflammation of the bronchial tubes in anyone with asthma. Other things, like cat dander or house dust, cause asthmatic inflammation only in those persons who are specifically allergic to cats or dust. Sometimes allergy testing is used to identify those things to which an individual is allergic with the goal of reducing or eliminating the amount of exposure to them.
Medications Can Help to Reduce the Inflammation of the Bronchial Tubes
The other principal way to reduce the chronic inflammation of the bronchial tubes is to take medications that suppress it. These are the anti-inflammatory medications of asthma. For long-term use, at present three different types of anti-inflammatory medications are available to treat asthma: cromolyn (brand name: Intal®), nedocromil (brand name: Tilade®), and the inhaled corticosteroids (brand names: Aerobid®, Azmacort®, Beclovent®, Flovent®, Pulmicort®, Qvar®, and Vanceril®). These medications can keep the inflammation of the bronchial tubes at a minimum while you take them; if you stop the anti-inflammatory medications, the inflammation of the bronchial tubes usually returns within a few weeks to what it was before taking the medications.
The "Non-Steroidal Anti-Inflammatory Drugs" Do Not Work for Asthmatic Inflammation
One type of anti-inflammatory medication works for the inflammation of arthritis but is not effective in asthma. These are called the "non-steroidal anti-inflammatory drugs" or NSAIDs. Examples include aspirin, ibuprofen, naproxen, Motrin®, Naprosyn®, Ansaid®, Tolectin®, and many others. Not only does this group of medications not help to treat the inflammation of asthma, in some persons with asthma—those with a sensitivity to aspirin—these medicines can bring on an attack of asthma, often one that is quite severe.
Preventive Treatment in Asthma
When swelling of the bronchial tubes and excessive mucus production cause cough and wheezing and shortness of breath, the anti-inflammatory medications can reduce these symptoms by reducing inflammation in the bronchial tubes. But why is it recommended for many persons with asthma that they take their anti-inflammatory medications every day, even when feeling well? By reducing the inflammation that is present, the "twitchiness" of the bronchial tubes lessens. One becomes less vulnerable to the possibility of developing an attack of asthma from swelling and spasm of the bronchial tubes. Anti-inflammatory medications are protective or preventive. They are used every day to prevent the symptoms of asthma from developing. The goal of successful asthma care is to prevent the symptoms of asthma from developing rather than having to relieve them with medications once they occur.
The Anti-Inflammatory Medications Are Safe to Use Every Day
The medications used to treat inflammation in asthma have been in use for more than 30 years. They are believed to be safe when used every day: they do not lose their effectiveness over time, they do not cause you to become dependent ("addicted") to them, and they do not cause medical problems even after decades of use.
No cure yet exists for asthma, but regular (daily) use of anti-inflammatory medicines can make the inflamed bronchial tubes of asthma more like normal, the symptoms of asthma gradually to go away, and the risk of a serious asthma attack far less likely.