Is Asthma an Autoimmune Disease?

Asthma is often caused by an immune system that overreacts to a substance that’s otherwise harmless. Some may assume asthma is an autoimmune disease, but asthma is not considered autoimmune. That’s because autoimmunity is a specific type of immune system reaction that’s different from what occurs in most cases of asthma.

This article explores the immune system response in asthma, how it’s different from autoimmunity, the relationship between asthma and autoimmune disease, and how to improve your immune function when you have asthma.

Is Asthma a Problem of the Immune System?

Your immune system uses a broad range of specialized cells, proteins, and chemical processes to keep dangerous pathogens (germs) out of your body and heal the damage caused by injuries or illness. Cytokines are a class of proteins produced by immune system cells.

When your immune system sends out cytokines to protect you, an inflammatory response is started. At this time, blood vessels expand, which allows immune cells to arrive at the site of the pathogen or where damage has occurred. Inflammation is part of the immune response aimed to rid the body of harmful invaders.

However, when an immune response is erroneously triggered when not needed—as it is in asthma—inflammation can cause unwanted effects. In asthma, the immune system reacts to triggers in your environment that shouldn’t bother it or shouldn’t cause such a large response.

About 80% of people with asthma have allergic asthma. Allergies are also a type of abnormal immune response in which the immune system reacts to normally harmless substances (allergens).

People with allergic asthma are triggered by allergens such as:

• Pet dander
• Bee stings
• Pollen
• Dust mites
• Certain medications

Nonallergic asthma triggers can include:

• Odors
• Viruses
• Exercise
• Cold or hot air
• Airborne irritants
• Psychological stress

If you don't have asthma or allergies, then, generally, these triggers will not cause a harmful response by your immune system.

Chronic Inflammation

When you have asthma, you always have at least some inflammation in your airways. This makes them hyperresponsive, meaning they’re extrasensitive to triggers. 

Then, when you’re exposed to triggers, the immune response directly causes an asthma attack, which leads to:

• More airway inflammation
• Extra mucus production
• Tightened muscles around the airways

That leads to classic asthma symptoms, which are:

• Wheezing
• Chest tightness
• Shortness of breath
• Coughing

You may have other symptoms as well, depending on the type of asthma you have.

Asthma Is Different From Autoimmunity

Asthma and autoimmunity both involve an inappropriate response from the immune system. However, the type of response is different.

In asthma, the immune system targets something foreign. In autoimmunity, the immune system targets substances produced by the body itself (self-antigens). This targeting attacks the body's own cells and tissues.

Individual autoimmune diseases each tend to target a different type of tissue, cell, or other substance in the body. For example:

• In rheumatoid arthritis, the immune system attacks the joint lining (synovium).
• In Sjögren’s syndrome, the immune system attacks moisture-producing glands.
• In Hashimoto’s thyroiditis, the immune system attacks the thyroid gland.

The immune system activation causes inflammation, as in asthma, but it also damages the area of the body targeted. This causes symptoms such as:

• Chronic pain
• Fatigue
• Recurring fever
• Swollen lymph nodes (“glands”)

Other symptoms depend on the area of the body targeted by the immune system and the extent of the damage. Examples include:

• Joint pain
• Gland malfunction
• Hormonal dysregulation

More than 80 autoimmune diseases have been identified, each with its own target(s).

Is Some Asthma Autoimmune?

Some research appears to suggest that nonallergic asthma (also called intrinsic asthma) may involve an autoimmune process. However, it’s too early for any conclusions to be reached.

It’s an important line of research, though. Intrinsic asthma is notoriously difficult to treat. Identifying an autoimmune component could expand the scope of treatments for intrinsic asthma to help with disease management.

Asthma Increases Risk of Immune Issues

The immune dysfunction of asthma may also predispose you to infections, especially viral ones. That’s because, when you have asthma, the epithelial cells that line your lungs cannot produce some types of interferon, a protein necessary for fighting off viral infections.

Respiratory infections are more common due to chronic inflammation, which allows pathogens to get into the respiratory system. However, that can’t explain a higher rate of other infections like:

• Skin infections
• Genital infections
• Urinary tract infections
• Digestive tract infections

The reason for this higher rate of infection is up for debate. But some researchers suspect it may have to do with the immune system’s “memory.”

When your immune system identifies a pathogen, it must figure out how to fight it. Part of the response is producing antibodies, which are specialized proteins that can attach to and lead to the destruction of a particular pathogen.

The next time the pathogen enters your body, your immune system will remember it and produce the proper antibodies to fight it much more quickly.

However, in some people with asthma, the immune system may not recognize pathogens that harmed the body in the past. The reasons why the immune system fails at recognizing and fighting pathogens are not fully understood and are an area of ongoing research.

Asthma also increases your risk of developing certain illnesses and of developing severe symptoms. These include:

• Influenza (the flu) (a respiratory illness, not the “stomach flu”)
• COVID-19
• The common cold
• Bronchitis
• Pneumonia

The added risk is likely due to asthma-related lung damage or weakened lung tissues.

Co-Occurring Asthma in Autoimmune Diseases

Having one type of immune system dysfunction may lead to other types. Studies have found that people with asthma have higher incidences of certain autoimmune diseases, including:

• Type 1 diabetes
• Crohn’s disease (a type of inflammatory bowel disease)
• Lupus
• Rheumatoid arthritis

This link isn’t fully understood, and research is ongoing.

Improving Immune Health With Asthma

Not only does asthma worsen respiratory illness, but those respiratory illnesses can also worsen asthma. To protect yourself, you may want to take steps to boost the health of your immune system, such as by doing the following:

• Eating a healthy diet: Focus on fruits and vegetables, lean protein, and whole grains. Limit saturated fat, cholesterol, added sugars, and salt.
• Get regular physical activity: Emerging research suggests a direct benefit to the immune system.
• Reach or maintain a healthy weight: Excess fat can impair your immune function and lower the effectiveness of some vaccines.
• Get plenty of sleep: Inadequate sleep can negatively impact your immune system and lead to many health conditions.
• Don’t smoke: Smoking makes it harder for your body to fight disease and increases your risk of immune-related illnesses.
• Drink alcohol in moderation: Heavy drinking can weaken the immune system.

To prevent infectious illnesses:

• Stay current with vaccines for influenza, COVID-19, pneumonia, and any others recommended by your healthcare provider.
• Wash your hands thoroughly and often.
• Avoid sick people.
• Stay home when you have symptoms.
• Wear a mask during outbreaks or peak seasons.

Effect of Asthma Medication on Immunity

Inhaled corticosteroids (ICS) are a common medication for people with asthma. They lower the population of immune-system cells involved in the condition.

However, this means they’re suppressing your immune system. In most cases, though, they only have this suppressing effect in the lungs—which is precisely what makes them effective against asthma.

Corticosteroids taken for a long time can be harmful and may increase your risk of:

• Community-acquired pneumonia
• Tuberculosis
• Other mycobacterial infections (infections by organisms related to tuberculosis)

On the other hand, steroids may protect you from some respiratory infections. Risks and benefits should be discussed with your healthcare provider.

If you’re on high doses of inhaled corticosteroids for a long time, it’s possible that a small amount of the drug may get past your lungs and into the rest of your body. It may then have a mild effect on your entire immune system.

This immunosuppression may cause mild side effects, such as slowing the healing of cuts or bruises. You may be able to reduce these side effects, or the risk of developing them, by:

• Rinsing your mouth and throat with water (or brushing your teeth) after using your inhaler
• Spitting out the water

Let your healthcare provider know if you notice possible side effects of immunosuppression while using inhaled corticosteroids.

Summary

Asthma involves an immune system that overreacts to normally harmless substances in your environment. Autoimmune diseases involve immune-system attacks on a healthy part of your body, such as joints, organs, or glands.

Having asthma can increase your risk of illnesses related to the immune system, including infectious diseases like the flu and COVID-19.

You may want to boost your immune health by improving your diet, getting more exercise and sleep, not smoking, and only drinking alcohol in moderation. It’s also smart to prevent infectious illnesses with basic habits like handwashing, getting vaccinated, avoiding sick people, and wearing a mask.