Can Asthma Cause Pneumonia?

And Can Pneumonia Cause Asthma?

Female patient talking with doctor
What are the links between asthma and pneumonia?. Jose Luis Pelaez/Iconica/Getty Images

Not long ago, I had a patient walk into my office complaining that they had asthma pneumonia. Not remembering asthma pneumonia as a disease I had learned about in medical school, I asked her what she meant by this condition. In talking with her, this person with long-term asthma thought her asthma had caused pneumonia for which she was seeking treatment. After her visit, I realized a number of people have asked me two similar questions about asthma pneumonia over the years:

  1. Can asthma cause pneumonia?
  2. Can pneumonia cause asthma?

Let's look at both of these questions and why they are important.

Asthma and Pneumonia

In order to discuss these questions we must first define these conditions. Asthma is a condition in which there is reversible obstruction of the airways. It is often associated with inflammation. Pneumonia, in contrast, is an infection of the lungs caused by viruses, bacteria, or fungi. (Chemical pneumonia is also a possibility).

Causes vs Risk Factors

It's also important to distinguish causes and risk factors. Unlike a cause, a risk factor increases the risk of something happening but is not the cause. For example, swimming in the ocean might raise your risk of drowning but it is not the cause of drowning. A risk factor may not cause a disease but could predispose you to developing the disease.

Asthma as a Cause of Pneumonia

We first became concerned after a link between the treatment of COPD and pneumonia was found.

At this time, a review of studies has confirmed that those who use inhaled steroids along with long acting beta agonists (LABA) (an inhaled steroid/LABA combination for COPD) are almost twice as likely to develop serious pneumonia as those who use a LABA alone. With COPD, it appears that Flovent (fluticasone) is associated with this complications somewhat more often than Pulmicort (budesonide).

A 2017 study found a similar scenario with asthma. People who were treated with inhaled steroids for asthma were 83 percent more likely to develop pneumonia those who did not use these inhalers. The increase in pneumonia risk, unlike that with COPD, with similar with both Flovent and Pulmicort.

It's not certain exactly why inhaled steroids increase pneumonia risk, though it's likely related to the effect of steroids on the immune system. It's long been known that people who use oral steroids (such as for rheumatoid conditions) are at greater risk of developing infections as the steroids "calm down" the immune response.

While you need to be mindful of this potential risk, it does not mean you should stop taking your asthma medications. While all asthma medications can have side effects, inhaled steroids can improve asthma symptoms significantly. Stopping inhaled steroids could potentially be more dangerous to your health than the risk of pneumonia noted here. The risk of illness and even death from severe asthma (status asthmaticus) is still a problem in the United States and around the world.

Can Pneumonia Cause Asthma?

The reverse question we hear is whether pneumonia can lead to asthma.

There is a tremendous amount of interest in an atypical bacteria called Mycoplasma pneumoniae that is most commonly responsible for walking pneumonia. Typically, this infection is thought to be self-limited, meaning that symptoms will resolve even if you are not treated with antibiotics. Scientists, however, have discovered that infection with Mycoplasma pneumoniae causes the following in animals:

  • Chronic infection: While thought to be self-limited, scientists continue to find evidence of the infection in the lungs of animals many months after the infection.
  • Chronic inflammation of the lungs: In mice studies, a single infection with Mycoplasma pneumoniae led to inflammation of the lungs for up to 18 months.
  • Abnormal pulmonary function tests: Over the same time period, scientists found evidence of both obstruction and hyperreactivity of the airways.

There is additional evidence of a relationship between pneumonia and asthma in humans. Scientists have found evidence that Mycoplasma pneumoniae may cause both an asthma exacerbation, and lead to the development of asthma in the first place. In particular, scientists have found:

  • Mycoplasma pneumoniae is more commonly identified among people hospitalized with asthma  compared to people hospitalized for other reasons.
  • Mycoplasma pneumoniae is commonly detected in children having an asthma exacerbation.
  • As many as 40 percent of kids infected with Mycoplasma pneumoniae will have wheezing and abnormal pulmonary function tests.
  • Children with asthma and Mycoplasma pneumoniae infection may be more likely to have abnormal pulmonary function tests both 3 months and 3 years following an infection.
  • Children exposed to Mycoplasma pneumoniae have higher levels of some markers scientists use in studying asthma called vascular endothelial growth factor (VEGF) compared to children without asthma. The association of VEGF and Mycoplasma pneumoniae suggests that the two are linked.

Asthma, Flu, and Pneumonia

You are more likely to hear about flu and pneumonia when flu is impacting your community but pneumonia is a known side effect of an influenza infection. While you are not at increased risk for developing a flu infection because you have asthma, you are at increased risk of developing a side effect such as pneumonia.

Your airways already have some degree of inflammation, swelling, and are more sensitive than those without asthma. A flu infection just makes the swelling and inflammation worse.

Normally your body filters out viruses and bacteria when they enter your body. The increased inflammation increases the chances that the flu virus is not removed and causes you problems. When the flu virus enters the alveoli or breathing sacs in your lung, the alveoli can fill up with fluid that leads to the symptoms of pneumonia such as chills, cough, fever, and trouble breathing.

If enough fluid builds up it can also lead to hypoxia or a decreased oxygen level in the blood. This will usually require hospitalization.

The flu virus can directly cause pneumonia or you could develop bacterial pneumonia that requires antibiotic treatment. When you have the flu you need to consider treatment. However, the best treatment is to get a flu immunization and prevent it altogether.

If you do get a flu infection, your doctor may want to treat yours with an antiviral. These drugs can decrease symptoms and may prevent more severe complications like pneumonia. Antivirals require a prescription from your physician.

Asthma Pneumonia—What About Antibiotics?

Given all of this, you may be wondering if people with asthma who have an asthma exacerbation should be regularly treated with antibiotics. Despite what we have previously discussed, there are no current recommendations to prescribe antibiotics for people with asthma. Studies looking at antibiotic treatment for Mycoplasma pneumoniae compared to placebo found improvement of asthma symptoms, but not lung function. While an area of study, there are no current recommendations to treat chronic asthma or asthma exacerbations with antibiotics.

Bottom Line on the Link Between Asthma and Pneumonia

There is clearly a link between asthma and pneumonia, though it doesn't appear that asthma causes pneumonia. What has been found is the one of the medications (inhaled steroids) used to treat asthma is linked with a predisposition for developing pneumonia. When looking at the opposite scenario, there is a fair amount of evidence that the bacterium which causes walking pneumonia may lead to the development of asthma. One way or another, the two conditions can go hand in hand, and contracting the flu if you have asthma can clearly raise your risk of going on to develop pneumonia.

Sources:

Hong, S. The Role of Mycoplasma Pneumoniae Infection in Asthma. Allergy, Asthma and Immunology Research. 2012. 4(2):59-61.

Kew, K., and A. Seniukovich. Inhaled Steroids and Risk of Pneumonia for Chronic Pulmonary Disease. Cochrane Database of Systematic Reviews. 2014. (3):CD010115.

Qian, C., Coulombe, J., Suissa, S., and P. Ernst. Pneumonia Risk in Asthma Patients Using Inhaled Corticosteroids: A Quasi-Cohort Study. British Journal of Pharmacology. 2017. 83(9):2077-2086.

Yin, S., Ma, F., and X. Gao. Association of Mycoplasma Pneumoniae Infection With Increased Risk of Asthma in Children. Experimental and Therapeutic Medicine. 2017. 13(5):1813-1819.

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