Steroids For Asthma: Benefits And Side Effects

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What is a steroid?

In general terms, steroids, also called corticosteroids, are a type of anti-inflammatory drug. The drug is similar to the hormones your adrenal glands make to fight inflammation and physical stress.

This type of steroid should not be confused with anabolic steroids, which mimic testosterone and are used to treat hormone problems in men, delayed puberty in boys, and muscle loss, but which are sometimes misused by bodybuilders and athletes.


Steroids can be used to treat:

  • Asthma

  • Severe allergies

  • Lupus, multiple sclerosis, and other autoimmune diseases

  • Skin conditions such as eczema

  • Some forms of cancer

They are powerful medicines that can have side effects, so they are typically taken for a short period or on an occasional basis. Alternatively, very low doses might be used.

Typically, your doctor will prescribe you steroids for the shortest period at the lowest possible dose. Some asthmatics may need to take steroids long-term, but this is generally at a very low dosage.

Are steroids safe for asthma?

Two kinds of steroids may be prescribed:

  • Oral corticosteroids

  • Inhaled corticosteroids

Oral corticosteroids, taken in pill or liquid form, are used to treat acute asthma flare-ups and are taken for a short period. Taking oral corticosteroids for an extended period carries significant risks, including the development of cataracts and osteoporosis.

Steroids used for the management of asthma are typically inhaled corticosteroids at a much lower dosage. These are generally well tolerated even for long-term use and in children, although there is some indication of a slight growth delay during the first year.

It's worth noting that the risks of poorly controlled asthma are higher than those of corticosteroids. Take your steroids as your doctor suggests, but make sure not to overdose.

How do steroids help treat asthma?

Steroids help control asthma symptoms by reducing inflammation in the airway, thereby easing symptoms such as breathlessness and coughing. This also helps to prevent your lungs from reacting to triggers.

Steroids can be administered through a preventer inhaler that supplies a low dose of steroids. The low dose, over time, reduces the reaction to triggers, and using the inhaler as recommended helps reduce the need for higher-dose steroid tablets.

How long does steroid treatment for asthma take?

If you have been given a preventer inhaler, you might need it for the rest of your life, although you may be able to move to a lower dose if your asthma is under control.

Some children grow out of asthma when they hit puberty, but in these cases, asthma may come back later in life. Asthma cannot be cured, but it can go into remission, sometimes for many years.

Steroid tablets are used to deal with a major flare-up or to bring asthma under control. Typically this means three to five days, although sometimes people may need to take them for weeks or months. If this is the case, the lowest effective dose will be prescribed.

The course lasts until symptoms have improved and may be extended if you are not feeling better by the end, so the ultimate length of treatment is highly variable. Always take the full course as prescribed by your doctor, even if your symptoms have improved or mostly gone away. As with antibiotics, it's important to finish the course.

Side effects of prednisone and other steroids

Steroids are very strong medicines that tend to have side effects. Side effects from a preventer inhaler are generally minimal and can include a sore throat and an increased risk of oral thrush. Using a spacer device and rinsing your mouth and throat with water after use can help prevent these side effects.

Side effects from oral steroids are more significant and include:

  • Upset stomach

  • Increased appetite

  • Mood swings

  • Increased risk of infection

  • Higher blood pressure

  • Depression

  • Weight gain

Sometimes high doses of steroids can cause elevated eye pressure and problems with memory and behavior, while longer-term use can result in thin skin, bruising, and slower wound healing. Steroids can also negatively impact blood sugar control if you have diabetes.

While you are on high-dose steroids, take special care to avoid catching viruses and other infections. Consider wearing a mask when in public indoor settings, make sure to wash your hands regularly, and follow good hygiene practices.

Steroids can suppress your immune system, making you more vulnerable to disease and likely to stay sicker for longer. This is typically not the case with low-dose steroids from a preventer inhaler.

When are inhaled steroids used for asthma?

Low-dose inhaled steroids are used as a preventive treatment for long-term control of asthma. Inhalers put the steroids right where they are needed to reduce inflammation in the airways. Most preventer inhalers contain steroids, although there are two alternatives:

  • Sodium cromoglicate

  • Nedocromil

These are less effective but might be prescribed if you don't tolerate steroids well.

Reliever or rescue inhalers used after an attack starts are different. They usually contain ICS-formoterol, meaning they combine a dose of corticosteroids with formoterol, which is a bronchodilator. Others, such as Ventolin, do not have steroids.

In the past, guidelines have promoted reliever inhalers without steroids but now allow for certain steroid combination puffers in adults and children six years old and over.

Some inhalers containing CFCs have been phased out. For some people with mild asthma, only a reliever inhaler is prescribed. Your doctor may start you off with only a reliever inhaler, but if you are needing it three times a week or more, you will almost certainly need a preventer inhaler.

The need depends on the frequency and severity of attacks.

Typically, you use your preventer inhaler twice a day and it takes 7 to 14 days for the effect to build up, and six weeks to gain full benefit.

Can steroids cause shortness of breath or make asthma worse?

In some cases, yes. Steroids are the go-to treatment for asthma management and are well tolerated by most people. However, there is a subset of patients whose asthma fails to improve or who experience worsening symptoms.

One reason for this is an allergy to aspirin. If you have a history of allergic reactions to aspirin, you can develop corticosteroid-induced bronchospasm.¹ This essentially means that you are allergic to the steroid medication. This occasionally also happens without a history of aspirin allergy. 

However, such a reaction is very rare — the incidence of adverse reactions to systemic treatment is 0.3%. Typically this means you will be given a preventer inhaler with one of the alternative medications. While these are not as effective, they are likely safer for you.

Another subset of patients that may not respond to steroid treatment for asthma are people with elevated levels of CXCL 10. This is an inflammatory protein, and high levels are associated with more severe asthma. The condition causes resistance to corticosteroid therapy and is experienced by 5%–10% of patients with severe asthma.

It is much rarer in people with mild to moderate asthma, likely because high CXCL 10 levels make asthma worse.

Both of these circumstances are relatively rare, but it is important to go straight to your doctor if your symptoms do not improve or worsen after taking corticosteroids, whether inhaled or oral.

When to see a doctor

People with asthma should get regular checkups. You should talk to your doctor right away if you are needing to use a rescue inhaler three or more times a week or if your asthma symptoms are getting worse. Also watch for the symptoms of oral thrush, which include:

  • Soreness and redness in the mouth

  • White patches on the inner cheeks, tongue, roof of the mouth, and/or the throat

  • A feeling of 'cotton' in your mouth

  • Pain while eating or swallowing

  • Cracking and redness at the corners of the mouth

  • Loss of taste

If you experience these symptoms, you should go to your doctor, who can give you an antifungal medicine to clear up the infection.

Talk to your doctor right away if your asthma symptoms get worse after starting corticosteroid treatment. You should also make sure that you are checked by your doctor for elevated eye pressure (glaucoma), which can be temporary or become chronic and require treatment. People on long-term oral steroid treatment need regular eye exams due to the risk of developing cataracts.

The lowdown

Many people with asthma are on low-dose inhaled steroids to control their condition. This is the best way to reduce the number of attacks and keep your asthma under control. For most people, preventer inhalers only produce mild side effects, such as a sore throat.

If you are having an asthma flare-up, your doctor may temporarily put you on oral corticosteroids. This is typically a short-term treatment designed to bring symptoms under control quickly, and the vast majority of people will not need the oral corticosteroids for long.

Typically, the benefits of steroids significantly outweigh the risks. However, a few people with severe asthma do not respond to steroid treatment, and a tiny percentage of the population is allergic to steroids. For most people, though, steroids are safe, well-tolerated, and effective.

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