Asthma and Nontuberculous Mycobacterial (NTM) Lung Disease

Reviewed by: HU Medical Review Board | Last reviewed: December 2022

An estimated 86,000 people in the United States live with nontuberculous mycobacterial (NTM) lung disease. And the number of people diagnosed with NTM – especially among women and older adults – is increasing each year.1

What is NTM lung disease?

NTM lung disease is an infection caused by bacteria that are commonly found in the environment. The bacteria that cause NTM are invisible to the naked eye. They are aerosolized, which means they are commonly found in dust, water, and soil particles in the air.2

In most cases, these bacteria particles do not cause illness. In fact, people come into contact with this bacteria on a daily basis through everyday activities like gardening, using tap water, and showering. Coming into contact with this bacteria does not affect most people. Their lungs are healthy enough to clear the bacteria on their own.2,3

But for people with underlying lung conditions or compromised immune systems, clearing NTM from the lungs is more difficult. When they breathe in the bacteria, it can damage their lungs.2

Symptoms of NTM include:2,3

  • Cough that does not go away
  • Shortness of breath
  • Excessive mucus
  • Fatigue
  • Respiratory infections that do not go away
  • Weight loss
  • Fever

NTM lung disease is a progressive disease. If symptoms are ignored or left untreated, NTM can worsen and may cause permanent damage to the lungs over time. This could lead to scarring of the lungs and, eventually, respiratory failure.1-3

How does NTM develop?

When a person with an underlying lung condition inhales NTM bacteria, the bacteria can infect the already damaged areas of the lungs. The bacteria hide in the body’s immune cells (macrophages) in the lungs. After getting past the macrophages’ defenses, the NTM bacteria multiply and spread. This leads to an infection. NTM can also develop after a person has had severe pneumonia.2

People most at risk of developing NTM are those with underlying lung conditions and weakened immune systems. Women and people over the age of 65 seem to be more at risk as well.1,2

Interestingly, a 2018 study found that using inhaled corticosteroids (ICS) was linked to an increased risk of NTM infection. ICS treatment is often a first defense against asthma symptoms. In the study, the NTM risk increased even further with larger ICS doses and longer ICS treatment time.4

Experts think this is because ICS use may change the lungs' natural defense system against infection. But more research is needed to understand the effects of ICS on overall lung health.4

How are asthma and NTM lung disease related?

People with asthma and other lung conditions like chronic obstructive pulmonary disease (COPD) and bronchiectasis are more at risk of developing NTM lung disease. That is because these conditions make it easier for NTM bacteria to infect the lungs.2

Because NTM symptoms are so similar to the symptoms of these other lung conditions, NTM often goes undiagnosed or misdiagnosed for months and sometimes years. Pay close attention to your symptoms, and take note if anything feels different.2

One key sign of a possible NTM lung infection is that your symptoms get worse. For example, you may have more flare-ups of excessive coughing or feel shortness of breath more often. Or your persistent cough may get worse despite your taking medicine.2

What do you do if you are concerned that you have NTM lung disease?

If you are having symptoms of NTM, talk to your doctor. Ask them if getting tested for NTM lung disease is right for you. Do not change or stop your current asthma therapy unless your doctor tells you to.

Your doctor may refer you to a pulmonologist or infectious disease specialist to get tested. This may involve a physical exam, a chest scan, and a mucus analysis. If you use an inhaler for your asthma, ask your doctor if the dosage is right for you and how often you should use it.

The sooner you are diagnosed with NTM, the sooner you can get proper treatment and start feeling better.

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