Thrush and Inhaled Steroids

A Common Fungal Infection Linked to Asthma Inhalers

Inhaled Steroids
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Inhaled steroids are commonly used to treat respiratory inflammation and to control symptoms of asthma. As important a tool as they are, inhaled steroids can sometimes increase the risk of developing a common fungal infection known as thrush (oral candidiasis).

Understanding Oral Thrush

Oral thrush is caused by a type of yeast, known as Candida, which normally lives in the mouth in small quantities.

When the immune system is weak and less able to control the fungus, it can suddenly grow excessively, resulting in soft, white patches in the mouth and/or sides of the tongue.

Thrush typically develops when the immune system is weak and is common in people with HIV and diabetes. It can also be caused by certain immune suppressive medications, such as chemotherapy drugs used to treat cancer. Corticosteroids (commonly referred to as steroids) are also known to suppress immune function.

Thrush is easily diagnosed by appearance alone. The white plaque is easily scraped off, although it can sometimes cause a burning pain. In severe cases, the fungus can spread into the throat and esophagus, making it difficult to swallow or even eat. There may also be noticeable cracking at the sides of their lip (a condition known as angular cheilitis).

Thrush is common among users of inhaled steroids. The risk of infection rises with increased dosage and/or frequency of use.

Oral steroids, regularly used in persons with severe asthma, is associated with both oral and vaginal candidiasis (yeast infections).

Preventing and Treating Oral Thrush

Among those who use inhaled steroids, thrush can often be prevented simply by rinsing the mouth or brushing the teeth after use. While it's not an absolute guarantee, especially if your use of inhalers is high, it may at the very least reduce the severity of an outbreak.

The use of a spacer with a metered dose inhaler may also help prevent or alleviate the symptoms of thrush. The device limits the amount of medication the mouth is exposed to while channeling treatment directly to the lungs. Unfortunately, many of the newer asthma treatments (like Advair, Pulmicort, and Asmanex) are dry powder inhalers which don't use a spacer.

Moreover, the powders from these inhalers don't dissolve all that well, so, even after brushing, there may still be residue clinging to the mouth and tongue. Alcohol-based mouthwashes like Listerine can sometimes help.

If you do develop oral thrush, your doctor may be able to prescribe an antifungal mouthwash or oral antifungal to treat the overgrowth. Even after treatment is complete, some people will need to continue using the mouthwash to keep the fungus from growing back.

A Word From Verywell

Like all medications, inhaled steroids pose certain short- and long-term risks. With that being said, they are considered among the most potent and effective drugs used to control asthma today.

To better avoid these side effects, always use the drug as prescribed and adhere to your treatment plan to minimize inhaled steroid use whenever possible.


Van Boven, J.; de Jong-van den Berg, L.; and Vegter, S. "Inhaled corticosteroids and the occurrence of oral candidiasis: a prescription sequence symmetry analysis." Drug Safety. 2013; 36(4):231-6.