How Inhaled Corticosteroids Affect the Immune System

It’s completely natural to have concerns about how medications impact your body. To help clear the air, we asked our Facebook community, as well as our team of respiratory therapists and asthma educators, to weigh in on a question we see often: Do inhaled corticosteroids suppress the immune system?

Here is what they said.

How do inhaled corticosteroids work in the lungs?

Response from John Bottrell, RRT

It is important to understand that asthma is a syndrome associated with increased airway inflammation. A main feature of this inflammation includes immune cells, such as T-cells, B-cells, and eosinophils, and the chemicals they release.

Inhaled corticosteroids greatly diminish the supply and the effects of these immune cells and chemicals. This benefit reduces airway inflammation, making your airways less sensitive to triggers.

Asthma attacks are less likely to occur when using these medications. They are also less severe and easier to control when they do happen. So, yes, inhaled corticosteroids do suppress the immune system—but primarily in your lungs to help you control your asthma.

How to manage the systemic side effects of inhaled corticosteroids

Sometimes, especially with higher doses, a small amount of the medicine can be absorbed into your system. When this happens, it can mildly suppress your immune system throughout your entire body.

In this case, you may notice mild side effects, such as bruises that do not seem to heal. However, studies show that rinsing your mouth and throat with water and spitting it out greatly reduces your risk for any systemic side effects of corticosteroids that asthma patients might worry about.

Do inhaled steroids cause fewer side effects than oral steroids?

Response from Theresa Cannizzarro, Respiratory Therapist

Corticosteroids mimic hormones your body naturally produces in your adrenal glands. When corticosteroids are prescribed at higher levels than your body naturally produces, they suppress inflammation.

It can also suppress your immune system. However, this is usually more likely when you are on higher doses of oral corticosteroids, such as prednisone.

Having your asthma better controlled with inhaled corticosteroids will not suppress your immune system to the extent that oral ones will. One burst of oral prednisone is the same amount of medication as an entire year's worth of inhaled corticosteroids.

The importance of targeting airway inflammation directly

Response from Lyn Harper, MPA, BSRT, RRT

Inhaled corticosteroids are an important part of treatment for a person with asthma. They reduce airway inflammation, the hallmark of the condition.

Most likely, you are on the lowest possible dose for the severity of your asthma. This is usually enough to treat the inflammation and avoid exacerbations.

One of the benefits of using a steroid inhaler is that it delivers medication directly to the area needed. This allows for much lower dosing with far fewer side effects.

Comparing dosages: Micrograms vs. milligrams

Response from Leon Lebowitz, RRT

All medications come with a long list of side effects that some patients may experience. Inhalers are no exception. However, the systemic absorption of aerosolized steroids is considered minimal.

For aerosols, less medication is needed since it is delivered directly to the lungs. The dose of inhaled corticosteroids is measured in micrograms, while oral steroids are measured in milligrams.

A microgram is one thousand times smaller than a milligram. This means only minuscule amounts of the steroid medication reach the bloodstream.

How to minimize the side effects of corticosteroid asthma treatments

Side effects can often be prevented by using proper technique and precautions. When breathed in, some medicine remains in the mouth and can be swallowed.

You can minimize the side effects of steroids left in your mouth in two ways. First, use a spacer tube with your steroid spray if recommended.

Second, gargle and rinse your mouth with water after inhaling. This removes medication residue while the portion that helps your asthma remains undisturbed in your bronchial tubes.

Why the benefits of asthma control outweigh the risks

Modern inhaled corticosteroids have been used for more than three decades by millions of people. No serious long-term adverse effects have been reported when taken at usual doses.

For adults, they do not cause degeneration of the respiratory passageways. They also do not predispose you to lung infections, cancer, or diabetes.

Remember that avoiding medication due to a fear of side effects can have consequences far worse than the potential side effects themselves. It is better to have your asthma under control now through a proper regimen.

How to discuss the side effects of corticosteroids with your doctor

Response from Lorene Alba, AE-C

Using a steroid inhaler can suppress your immune system, so it is important to talk to your healthcare provider. You should discuss the risks, benefits, and potential side effects of taking these medications.

If you take an oral steroid, the medicine is ingested and enters the bloodstream. This can cause side effects such as weight gain and mood swings.

To stay healthy, focus on eating well, getting plenty of sleep, and managing stress. These habits help keep your immune system working well and reduce the chance of catching infections.

Editor’s Note: The information in this article cannot be substituted for medical advice. Always consult your doctor before beginning, ending, or changing treatments.