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Expert Series: Do Inhaled Corticosteroids Suppress Your Immune System?

We asked our community if inhaled corticosteroids suppress the immue system. As we saw this question pop up in our forums and on our Facebook page we thought we’d ask our experts to respond. Read their answers below:

Response from John Botrell, RRT:
john bottrell
It’s important to understand that asthma is a syndrome associated with increased airway inflammation. A main feature of this inflammation are immune cells (such as T-Cells, B-Cells, and eosinophils) and the chemicals they release (such as leukotrienes). Inhaled corticosteroids greatly diminish the supply, and greatly diminish the effects, of these immune cells and chemicals. The benefit here is a reduction in airway inflammation, making your airways less sensitive to asthma triggers. Asthma attacks are less likely to occur, and are less severe and easier to control when they do occur. So, yes, inhaled corticosteroids do suppress the immune system — but only in your lungs to help you control your asthma.

Sometimes, especially with higher doses of inhaled steroids, 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 some mild side effects such as bruises that don’t seem to go away.1 However, studies seem to show that rinsing your mouth and throat with water, and then spitting it out (as opposed to swallowing), greatly reduces your risk for any systemic side effects to inhaled corticosteroids.

Response from Theresa Cannizzarro, Respiratory Therapist:

Corticosteroids mimic what hormones your body naturally produces in your adrenal glands. When corticosteroids are prescribed at higher levels than what your body naturally produces, it suppresses inflammation. It can also suppress your immune system. However, this is usually more likely when on higher doses of oral corticosteroids, such as prednisone. Having your asthma better controlled with inhaled steroids won’t suppress your immune system to the extent that oral ones will. One burst of oral corticosteroids (prednisone) is the same amount of medication as an entire year’s worth of inhaled corticosteroids.

Response from Lorene Alba, AE-C:

Inhaled corticosteroids can suppress your immune system, so it’s important to talk to your health care provider to discuss the risks and benefits of taking these medications. If you need a steroid to manage your asthma, it’s best to take a daily inhaled corticosteroid; when inhaled the medication goes directly into your lungs. If you take an oral steroid, the medicine is ingested and goes into the bloodstream, which can cause side effects such as weight gain and mood swings. Eating well, getting plenty of sleep and managing stress will all help keep your immune system working well and reduce the chance of catching an infection like pneumonia.

Response from Lyn Harper, MPA, BSRT, RRT:
lyn harper

Great question! Unfortunately, there are side effects to taking steroids – inhaled or oral. However, the risk of suppressing the immune system with inhaled corticosteroids is far less than with the use of systemic steroids.
For a person with asthma, inhaled steroids are an important part of treatment. They reduce the airway inflammation that is the hallmark of asthma. So, when prescribing inhaled steroids most doctors weigh carefully the benefits vs. the risks. Most likely you’re on the lowest possible dose for the severity of your asthma – enough to treat the inflammation and avoid exacerbations. One of the benefits of inhaled steroids is that they are being delivered directly to the area needed, which is one of the reasons a much lower dosing can be used with far fewer side effects. In fact, it takes about a year of inhaled steroids to equal a 5-day course of oral steroids prescribed during an exacerbation.

Response from Leon Lebowitz, RRT
In general, the short answer is ‘no’. Although there have been some very interesting discussions regarding this concern on our website and Facebook page, there is evidence that shows inhaled corticosteroids (ICS) do not suppress our immune system. It should be noted that all medications come with a veritable laundry list of side effects that may be experienced by some patients using them. Inhalers are no exception. However, the systemic absorption of aerosolized steroids is considered to be minimal. This means that only minuscule amounts of the aerosolized steroid medication are getting into the bloodstream. This is by design, as the target for the aerosolized steroid being used is the lung parenchyma or tissue. As well, only very small amounts of the steroid medication are delivered from the inhaler with each dose or ‘puff’. For aerosols, less medication is needed (when compared to oral medications) since the aerosol is delivered directly to the lung specifically. As an example, the dose of inhaled steroids is measured in micrograms (mcg) as compared to milligrams (mg), which is the unit of measure for oral steroids. A microgram is one thousand times smaller than a milligram.
Side effects of using ICS can be prevented by using proper technique and precautions. When breathed in, some steroid medicine remains in the mouth and can be swallowed into the stomach and from there absorbed into the bloodstream. You can minimize any effect from steroids left behind in your mouth in two ways. First, use a spacer tube with your steroid spray (if recommended, as spacers cannot be used with dry powder inhalers). Medicine that would otherwise land on your tongue and mouth stays in the spacer chamber. The part of the spray that passes through the spacer also tends to pass through your mouth and proceed down onto the bronchial tubes. Second, gargle and rinse your mouth with water (and spit it out) after inhaling the steroid spray. Rinsing removes any medicine residue from your mouth. The portion of the medicine that helps your asthma remains undisturbed on your bronchial tubes.
The current generation of steroid inhalers first began to be used in the mid-1960s. For more than three decades they have been prescribed for millions of people with asthma and other lung diseases worldwide. No serious long-term adverse effects have been reported. For adults, given in the usual doses, they do not cause degeneration or atrophy of the normal tissues of the respiratory passageways. They do not predispose to lung infections and they do not cause cancer, diabetes, or high blood pressure. 2
Remember that not taking inhaled steroids for fear or concern of side effects may have real consequences that can be far worse than potential effects in the future. It’s better to have your asthma condition and exacerbations under control now, through a proper, prescribed medication regimen.

This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.

  1. Steroid Bruising (Accessed April 2017)
  2. What are the side effects of inhaled steroids if used for many years? (Accessed April 2017)


  • Davo
    2 months ago

    Can someone please give me there opinion,I’m 66yrs old been on Pulmicort turbuhaler it made me nauseous and stomach bloating big time then changed to flixotide it also caused severe weight gain stomach bloating my asthma seems worse on these meds shortness of breath ,my dr just says give it bit longer it’s ok for him I feel terrible an asthma worse

  • Leon Lebowitz, RRT moderator
    2 months ago

    Hi again, Davo, and thanks for your post. I remember you mentioning in a previous post, about your doctor changing you to this medication. You may want to discuss the way you are feeling (on this medication), with him, especially since you’ve been on it for awhile now, if I remember correctly, and you are not feeling well. What do you think? Leon (site moderator

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