Asthma

Asthma life stories

Asthma is a chronic lung disease that causes inflammation and narrowing of the airways. This narrowing can cause episodes of wheezing, chest tightness, shortness of breath, and coughing.  

Asthma symptoms are usually controlled by inhaled medications that treat inflammation in the airways or relax the smooth muscle that tightens the airways. However, some people do not respond adequately to these medications.  

If you are already using high dose medicines, reducing risks, and following your treatment plan yet your asthma remains uncontrolled, this is a sign that you may be suffering from severe asthma. It’s important to consult with your health care provider to determine if you suffer from severe asthma or uncontrolled asthma, as treatment plans may differ.  

Getting diagnosed with severe asthma can stop you in your tracks. It’s normal to feel fearful and concerned—how will this affect your life and those you love? It’s also normal to feel a sense of relief with the diagnosis. With a proper treatment plan, you’ll still be able to better manage your disease. Hear the stories of Amy and April, two women living their best lives in spite of their diagnoses. 

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On demand webinars 

In collaboration with GSK, our educational webinars are designed to help you better understand the symptoms of severe asthma. They also will help you navigate your journey through your diagnosis by providing real stories from the people who’ve been there.

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This educational campaign on the burden of disease is funded by GSK and developed in collaboration with CHEST.

Infographic References:

• Varricchi G, Bagnasco D, Borriello F, Heffler E, Canonica GW. Interleukin-5 pathway inhibition in the treatment of eosinophilic respiratory disorders: evidence and unmet needs. Curr Opin Allergy Clin Immunol. 2016 Apr; 16(2):186-200. 
• Chung KF, Wenzel SE, Brozek JL, Bush A, Castro M, Sterk PJ, Adcock IM, Bateman ED, Bel EH, Bleecker ER, Boulet LP, Brightling C, Chanez P, Dahlen SE, Djukanovic R, Frey U, Gaga M, Gibson P, Hamid Q, Jajour NN, Mauad T, Sorkness RL, Teague WG. International ERS/ATS guidelines on definition, evaluation and treatment of severe asthma. Eur Respir J. 2014 Feb;43(2):343-73. 
• Global Strategy for Asthma Management and Prevention. Global Initiative for Asthma. 2019 Update. https://ginasthma.org/wp-content/uploads/2020/04/GINA-2020-full-report_-final-_wms.pdf  

Mythbuster References:

• World Allergy Organization. https://www.worldallergy.org/adrc/
• Chung KF, Wenzel SE, Brozek JL, Bush A, Castro M, Sterk PJ, Adcock IM, Bateman ED, Bel EH, Bleecker ER, Boulet LP, Brightling C, Chanez P, Dahlen SE, Djukanovic R, Frey U, Gaga M, Gibson P, Hamid Q, Jajour NN, Mauad T, Sorkness RL, Teague WG. International ERS/ATS guidelines on definition, evaluation and treatment of severe asthma. Eur Respir J. 2014 Feb;43(2):343-73. 
• Global Strategy for Asthma Management and Prevention. Global Initiative for Asthma. 2019 Update. https://ginasthma.org/wp-content/uploads/2020/04/GINA-2020-full-report_-final-_wms.pdf

About Severe Asthma

About 5% to 10% of people with asthma have severe asthma. Despite various treatments, their asthma is not controlled. If you have severe asthma, you might experience more:

• Daytime and nighttime symptoms
• Flare-ups
• Hospital visits
• Serious damage to the lungs

Identifying Severe Asthma

New research has identified four molecular markers in the type 2 inflammation pathways that show how specific cells react and lead to greater inflammation. Identifying molecular targets can help your provider determine the best treatment for your severe asthma.

The molecular targets in your body vary depending on the type of asthma you have. An increase in these biomarkers is associated with more asthma flare-ups and limited asthma control:

• IgE (immunoglobulin E): IgE is normally found in small amounts in the body, but sometimes it increases dramatically when exposed to allergens that trigger a reaction in your body. IgE can also stimulate other cells to behave in ways that increase inflammation.

• Interleukin 4 (IL-4) and activation of its receptor (IL-4Rɑ) do three things: It signals other cells to begin production of inflammatory substances. It sends eosinophils (white blood cells that cause inflammation in high amounts) to the different parts in the body, including the lungs. And it causes the smooth muscles around the airway to contract.  
  
• Interleukin-5 (IL-5) and activation of its receptor (IL-5Rɑ): activates eosinophils and directs them to circulate to the sites of inflammation.  
  
• Thymic stromal lymphopoietin (TSLP): TSLP activates different cells that stimulate an allergic response and increases eosinophil levels and leads to smooth-muscle contraction. 

Type 2 inflammation pathways

Symptoms and triggers

Asthma is a disease that involves two body reactions: swelling and tightening of the airway. These two factors cause your airway passages to be sensitive to the environment.

You can be symptom free for years by using medications and limiting your exposure to triggers. The most common asthma symptoms are:

• Shortness of breath
• Wheezing
• Cough
• Chest discomfort
• Not being able to do your daily activities

Common Asthma triggers

Anything that causes the airway to be inflamed, swollen, or tighten is an asthma trigger. Reducing exposure to your asthma triggers is the first important step in keeping your airways open and managing your asthma.

Illnesses that can affect Asthma

Sometimes other illnesses may masquerade as or trigger asthma. Ask your health-care providers whether you have any conditions that contribute to or may trigger asthma.

Other lung diseases, such as COPD (chronic obstructive pulmonary disease), have symptoms that are similar to those for asthma. This similarity can make diagnosing asthma harder. Other illnesses contribute to airway constriction, which can make asthma worse. They include:  

• Hay fever (allergic rhinitis)
• Sinusitis
• Obesity
• Vocal cord dysfunction

Diagnosis

You should find an asthma specialist to get an accurate diagnosis. To determine whether you have asthma, your health-care provider will typically perform these tests:

• Physical exam and health history: Your provider will do a physical examination and ask about your health history and your family’s health history (family history).
• Spirometry: This lung function test measures how much air you can move in and out of your lungs and how fast you can do it. You will be asked to blow into the mouthpiece of a handheld device (called a spirometer) as fast and hard as you can a few times.
• Methacholine challenge: During this test, you are exposed to small and increasing doses of a medication called methacholine, which causes your airways to narrow. When your airways narrow by 20% compared with your baseline reading, the test is over and you get medication to open your airways again.
• Allergy tests: These tests can help your provider discover what allergens might trigger your asthma.
• Fractional exhaled nitric oxide (FeNO) test: This test helps your health-care provider determine how much inflammation you have in your airways.
• Eosinophil test: This test determines the eosinophil cell count in your blood.

Examining Asthma with phenotypes

Not long ago, it was believed that asthma was experienced the same way by all people. Today, science has shown that people react very differently to asthma triggers. By identifying your unique physical reactions in your cells, your treatment can be tailored to your specific biological changes.

Today, asthma is examined through phenotypes, which are observable traits or characteristics that are a result of how your genes interact with your environment.

A classification system groups asthma based on clinical, genetic, and environmental responses called biomarkers. The advantage of using this system is that it can help predict how your body will respond to specific treatments. The major phenotypes associated with asthma are based on the type of inflammation that is the cause.

Treatment for type 2 inflammation relies on biomarker testing. Biomarkers are observable biological, physiological, and molecular signals that indicate what is happening in the cells of the body. Biomarker testing shows exactly how your body reacts to inflammatory triggers and can help your provider recommend targeted therapies tailored to treat your physical response.

When to see a health-care provider for Asthma

Contact your health-care provider if you experience:

• Shortness of breath, coughing, or wheezing that affect activities of daily living
• Daytime asthma symptoms two or more days per week
• Shortness of breath that is not helped by a rescue inhaler
• Symptoms that cause you to miss school or work
• Symptoms that result in urgent care or emergency department visits
• Side effects from medication
• Oral infections, such as thrush

Treatment

There are many medications used to treat asthma. Some focus on reducing inflammation, some work on relaxing the muscles that surround the airways, and some help reduce mucus production. The most important thing to remember about asthma medications is that they work only if you take them as prescribed.

Most medications used to treat adults and older children with asthma can also be used for younger children. Parents need to work closely with their health-care providers to keep their child’s asthma well controlled as their bodies change and grow.

Asthma treatments

Asthma treatments target inflammation or bronchospasm:

Some of the most frequently prescribed medications for adults and children include the following treatments.

Inhalers

Inhalers are the most common type of asthma medication. The two types of inhalers are:

Rescue inhalers

Also known as quick-relief inhalers, rescue inhalers provide quick, short-term relief during a flare-up (asthma attack). This form of treatment contains a medication (called a bronchodilator) that rapidly widens your airway. It works by relaxing the outer muscles surrounding the airways to prevent the tightening that narrows the airways and limits air flow.

Examples of rescue inhalers include:

• Albuterol (ProAir^® HFA, ProAir^® Respiclick, Proventil^® HFA, Ventolin^® HFA)
• Levalbuterol (Xopenex HFA^®)

Control inhalers

Also known as long-term control, maintenance, or preventer inhalers, this form of medication usually contains a steroid that reduces inflammation. Daily use of a control inhaler, even when you feel well, is important to prevent asthma from worsening. If your asthma is mild, you might be able to use this type of inhaler only when you have symptoms.

Examples of control inhalers with steroids include:

• Budesonide (Pulmicort Flexhaler^®)
• Beclomethasone dipropionate (Qvar RediHaler^® HFA)
• Fluticasone furoate (Arnuity^®, Ellipta^®)
• Fluticasone propionate (Flovent Diskus or HFA)
• Mometasone furoate (Asmanex^® HFA or Twisthaler^®)
• Ciclesonide (Alvesco^®)

Long-acting bronchodilator

Another type of controller medication includes a long-acting beta-agonist (LABA), which works to relax the muscles over a longer period of time. This type of medication should always be used in combination with corticosteroids in the inhaler. 

Examples of inhaled corticosteroids (ICSs) and LABAs include:

• Advair Diskus^® or HFA
• Breo^® Ellipta^®
• Dulera^®
• Symbicort^®
• Wixela™
• AirDuo RespiClick^®

Single maintenance and reliever therapy (SMART) inhalers

Some medications act as both a rescue inhaler (because they are fast acting) and a control inhaler (because they are long lasting). Examples include:

• Budesonide and formoterol fumarate dihydrate (Symbicort^® HFA)
• Mometasone furoate and formoterol fumarate dihydrate (Dulera^®)

Other medication options

When your asthma is not controlled by using rescue or control inhalers, you may need other medications.

Long-acting muscarinic antagonists (LAMAs)

These medications reduce mucus and widen airways. This allows more air to flow through. For example: 

• Tiotropium (Spiriva®) 

An ICS, a LABA and a LAMA can be combined into a single inhaler. For example: 

• Fluticasone, vilanterol, umeclidinium (Trelegy®) 

Oral corticosteroids

Oral corticosteroids are a kind of anti-inflammatory medication that reduces swelling and mucus inside the airway. This medication is used for asthma flare-ups and for severe asthma.

Leukotriene modifiers

Leukotrienes are chemicals that cause inflammation and excess mucus production in the lungs. The body releases leukotrienes when it comes into contact with an allergic trigger. Leukotriene modifiers are medications that reduce the number of leukotrienes the body releases. This prevents them from causing greater inflammation and increased mucus.

Biologics

Biologics take asthma treatment to a new level. They target a specific cell or protein in the body to prevent inflammation in the airways. Biologics are delivered via a shot or intravenous infusion given every 2 to 4 weeks. Your provider may recommend a biologic if:

• Your asthma is not controlled with standard inhalers
• You have frequent asthma flare-ups
• You use oral steroids frequently

Six biologics are available for the treatment of asthma: 

• Benralizumab (Fasenra®) 
• Dupilumab (Dupixent®) 
• Mepolizumab (Nucala®) 
• Omalizumab (Xolair®) 
• Reslizumab (Cinqair®) 
• Tezepelumab (Tezpire®) 

How to take your Asthma medications

Most asthma medications come as sprays or powders delivered using an inhaler. When you inhale the medication, it goes into the airways of the lungs, right where it is needed.

The most familiar type of asthma inhaler is the metered-dose inhaler (MDI). This pressurized device releases medication in a fine spray for you to inhale. Small children and others may also use a nebulizer to deliver their medication. This machine turns liquid medicine into a mist that can be inhaled slowly over 10 to 15 minutes.

Ask your health-care provider or pharmacist to show you how to use your inhaler. Also read the instructions that came with the inhaler and follow the priming and cleaning directions carefully.

Using a metered-dose inhaler

Each brand of MDI operates and needs to be maintained differently. Check the patient instruction sheet that came with your inhaler for details.

Priming and counting doses

When an MDI is new or hasn’t been used in a while, the ingredients may separate. Priming (releasing one or more sprays into the air before using it as treatment) helps ensure the dose you inhale has the right amount of medication.

Even the most perfectly timed inhalation won’t help if there’s no medicine left in the inhaler. You need to count each dose and each priming spray. By keeping count, you will know when to replace your inhaler. Many MDIs now have dose counters built in to make it easy for you to keep track of how much of your inhaler you have used.

How to inhale properly

You must inhale the spray quickly enough to prevent it from landing on your tongue or inside your cheek, but slowly enough to let it get deep into your lungs.

Many people, especially children, have trouble inhaling from an MDI. A common solution is a valved holding chamber (VHC) or spacer. These devices are easy to use and improve the delivery of the medication to the lower airways. They also decrease two common side effects of medication delivery: thrush (candidiasis) and hoarseness (dysphonia).

• VHC: A VHC attaches to the MDI and has a one-way valve that allows you to spray the medication into the chamber and inhale it when you are ready or over several breaths. It can also be used with a mask attachment for young children and others.
• Spacer: A spacer is an open tube placed on the mouthpiece of the MDI. It increases the distance between the MDI and the patient’s mouth and directs the medicine into the chamber. Patients must still coordinate breathing with the release of spray from the inhaler.

Instructions for using inhalers

Follow these instructions to help you understand how to use your inhaler: 

Guides for specific inhaler devices

Find step-by-step instructions on how to use almost any inhaler on the market.

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Managing Asthma

Asthma tends to change a lot over time, with symptoms that come and go. This can lead to changes in your asthma severity.

To manage symptoms, you’ll need to work with your health-care provider. That means keeping regular appointments even when you feel fine. Well visits help you keep your asthma under control and identify problems early on. Having a team who knows you also makes it easier to maintain effective treatment plans and deal with emergencies.

Your Asthma Action Plan

An important part of your asthma management is a written Asthma Action Plan. Your health-care provider will work with you to create an Asthma Action Plan that tells you:

• What medicines to take and when to take them.
• Things you should do to prevent symptoms and deal with flare-ups.

Your Asthma Action Plan outlines treatment according to colored zones:

• Green Zone: Means you are doing well
• Yellow Zone: Means your asthma is getting worse
• Red Zone: Means you need immediate medical attention

Controlling your asthma may seem like a lot of work at first, but turning these steps into daily habits now can help you live a normal life. Remember to:

• Take action to control or avoid your individual asthma triggers.
• Keep a daily diary of your asthma symptoms to share with your health-care provider.
• Take your long-term control medicines daily or as prescribed.
• Always carry your quick-relief medicine with you.

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When to see an Asthma specialist

You may need to see a specialist (an allergist or pulmonologist) if you continue to have symptoms that disrupt your sleep or everyday activities, even after following your management plan. The National Institutes of Health asthma guidelines recommend seeing a specialist if you:

• Have had a life-threatening asthma episode
• Are not responding to treatment after 2 to 4 weeks
• Have persistent asthma symptoms, limited physical activity, and frequent flare-ups
• Need continuous high-dose ICSs or more than two courses of oral corticosteroids in 1 year
• Need additional testing, such as allergy tests, complete spirometry breathing tests, rhinoscopy, or bronchoscopy
• Are being considered for immunotherapy
• Have conditions that complicate your asthma, such as severe hay fever, sinusitis, GERD, or exercise-related breathing problems
• Need more education on complications of therapy or allergen avoidance at home, school, or work

Coping with an Asthma attack

Know the danger signs of a serious asthma attack:

• Severe shortness of breath (gasping for air)
• Inability to talk well (not being able to speak in a full sentence)
• Difficulty walking
• Lips or fingernails turning blue

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If you experience these danger signs, you are having a major asthma attack. Go to the emergency room or call 911 immediately!

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Signs of less severe asthma attacks:

• Coughing, sneezing, itchy throat
• Tight chest, wheezing
• Shortness of breath
• Waking up at night
• Fast heartbeat

When you feel an attack coming, follow these three steps:

• Get away from the trigger that started your attack.
• Take your quick-relief medicine as soon as you notice symptoms and then follow your Asthma Action Plan, which may advise you to take your controller medicine as well.
• If you still have wheezing and shortness of breath, contact your health-care provider or get emergency help.

Women with Asthma

Asthma is particularly challenging for women. Compared with men, women are more likely to have asthma, their asthma is more severe, and they have worse outcomes. Female hormones are thought to be the main contributor to higher rates of asthma in women.

Part of the problem is that female biology makes breathing harder—normally and at all ages—than does male biology. Women have smaller lungs, smaller airways, and smaller breathing muscles. They also have smaller rib cages, which limits the amount of air that can enter the lungs, and smaller chest wall muscles. These differences affect air flow, lung volume, and the amount of effort required to breathe.

Risk factors

Although the risk factors for women are the same as those for men, three asthma risk factors occur more often for women.

Obesity

Being overweight increases the likelihood of getting asthma for both men and women, but can make control particularly difficult for women.

Environmental triggers

Poor air quality in the home or the workplace, particularly in cities, increases the likelihood of women developing asthma.

Smoking

Tobacco smoke, secondhand smoke, and vaping all contribute to higher incidence of asthma in women.

Girls and Asthma

Before age 18, boys are more likely to have asthma than girls. In fact, boys are twice as likely as girls to be hospitalized for an asthma exacerbation. But as puberty begins and male and female hormones kick in, the numbers shift—more women have asthma than men.

This difference is likely associated with the male and female hormones. As boys reach puberty, testosterone increases, which reduces asthma reactions that lead to inflammation and mucus production in the lungs. Conversely, estrogen and progesterone (the primary female hormones) have been shown to increase airway inflammation, leading to more asthma symptoms.

It’s not the female hormones themselves that trigger asthma symptoms. It’s the fluctuation—the ups and downs—of these hormones that affects asthma at key points in a woman’s life—puberty, periods, pregnancy, and perimenopause.

Periods and Asthma

For about half of women who have asthma, asthma symptoms worsen right before (4 to 5 days) and during their periods. That’s because estrogen and progesterone levels decrease to their lowest levels in the reproductive cycle the final week before your period.

The decline in female hormones narrows the airways or affects cells in the immune system, which can cause an asthma attack. This is called premenstrual asthma. Most hospitalizations for women with asthma happen in the days before their periods begin.

For most women with asthma, paying close attention to your triggers before your period can help you avoid increases in symptoms. For women who experience severe asthma symptoms around their periods, hormone therapy may be recommended, such as birth control pills, patches, or injections.

Pregnancy and Asthma

Controlling asthma is very important if you are pregnant. Healthy baby development relies on oxygen delivered to the fetus from the mother’s bloodstream. That means women with asthma who are pregnant need to keep their airways open and their breathing clear to ensure that the fetus gets plenty of oxygen. Fortunately, asthma affects only about 4% to 8% of pregnant women.

Asthma in pregnant women is unpredictable. For about one-third of this group, asthma symptoms worsen. In another third, asthma symptoms stay the same. For another third, asthma symptoms improve. Almost half of pregnant women with asthma have an asthma attack during their pregnancy. If asthma control gets worse during pregnancy, the symptoms tend to increase during weeks 24 to 34.

Poorly controlled asthma during pregnancy carries risks. Mothers with uncontrolled asthma are more likely to develop complications, including:

• Pre-eclampsia (dangerously high blood pressure)
• High blood pressure
• Higher rate of C-section (cesarean delivery)
• Preterm or premature birth
• Low birth weight for the baby
• Bleeding during pregnancy
• Bleeding after giving birth
• Anemia
• Blood clots to the lungs

Keeping asthma controlled during pregnancy requires careful monitoring. Make sure your obstetrician is aware of your asthma and that your asthma specialist knows about your pregnancy as early as possible. Most asthma medications are safe to take during pregnancy. Meet with your asthma specialist to review your medications and Asthma Action Plan for your pregnancy.

You’ll also need to have your medications on hand during labor and delivery. About 10% of women with asthma have symptoms during labor and delivery, but an asthma attack is very rare.

Women who experience changes in their asthma during pregnancy—either worsening or improving—generally go back to their prepregnancy asthma levels within 3 months of birth. It is safe to use both quick-relief and controller inhalers while breastfeeding.

Perimenopause or menopause and Asthma

The transition to menopause—called perimenopause—begins around age 45. During this time, women experience changes in the length, frequency, and severity of their periods. Because of fluctuations in estrogen and progesterone levels, women with asthma often see an increase in asthma symptoms and severity. The changing peaks and valleys in women’s hormones can trigger inflammation in the lungs. The good news is that once menopause takes place, the reduction in female hormone levels often leads to fewer and less severe asthma symptoms.

Taking hormone replacement therapy (HRT) to reduce the symptoms of menopause is a mixed bag for women. If you have a history of asthma and begin HRT at menopause, you may still see a reduction in your asthma. But some women who have not had asthma and begin taking HRT when they reach menopause may be likely to develop new asthma than women who do not take HRT, and their asthma is often more severe and difficult to treat. Talk to your doctor before beginning HRT to determine whether this treatment will be beneficial for you.

Older women and Asthma

Many women experience asthma symptoms for the first time around age 50 or older. Asthma tends to be more severe in women who are over age 65, and they have higher death rates than the general population. Women in this age group are also twice as likely as men to visit emergency departments, and they have the highest rate of hospitalizations for asthma of any group.

Older women are at risk for negative effects from inhaled corticosteroids (ICSs). ICSs can contribute to low bone density and increase the risk of fractures. Older women also have a higher rate of obesity (42.3%) than the general population (35.7%). Asthma occurs more often in women who are obese than in those who are not.

Depression can be a challenge for older women with asthma. Depression can contribute to worse asthma control, lower quality of life, and less adherence taking controller medications.

The best defense is to stick to your Asthma Action Plan and see your health-care provider regularly to prevent worsening symptoms.

Understanding how asthma is treated and how to live well with it will improve your quality of life. Use the CHEST Foundation’s resources to learn more about asthma.

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Resources

Use this information to get answers and support.

Asthma support groups and education

Look for local asthma support groups in your area or online support groups. You can also ask your health care-provider about support groups in your area. Your insurance provider may also have asthma educators who provide education and resources.

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Asthma glossary

Being able to talk about your asthma is a big part of managing your asthma. Here are some terms you might hear from your health-care provider:

Adult-onset asthma: Asthma that develops during adulthood.

Allergen: Anything that causes an allergic reaction, such as pollen, pet dander, and dust mites.

Allergic asthma: Asthma triggered by allergic reactions or allergic diseases; often starts in childhood.

Allergy test: Any of various tests that help your asthma specialist determine what allergens might be triggering your asthma.

Antibiotic: On special circumstances, some types of antibiotics (macrolides) can be used to treat the inflammation non Type 2 asthma. 

Anti-inflammatory: In asthma, anything that reduces or prevents swelling or thickening of the airways; a type of medication that reduces inflammation.

Asthma: A chronic lung disease that makes it hard to breathe. There are 4 levels: intermittent, mild persistent, moderate persistent, and severe persistent.

Asthma trigger: Anything that causes the airway to be inflamed or swollen, or to tighten.

Biologic: A type of medication that targets a specific cell or protein in the body to prevent inflammation in the airways.

Biomarker: Molecular signal that helps your health-care provider know what is happening in the cells of the body.

Biomarker testing: A test that tells your health-care provider exactly how your body is reacting to inflammatory triggers.

Bronchodilator: A medication that relaxes airway muscles or prevents them from tightening. Long-term bronchodilators work to relax the muscles continuously over time; short-acting bronchodilators are used for quick relief when a flare-up occurs.

Bronchospasm: Tightening of the muscles around the outside of the airways; this causes narrowing of the airways.

Chronic obstructive pulmonary disease (COPD): is a pulmonary condition that is common, preventable and treatable that is characterized by persistent respiratory symptoms and abnormal lung function that is due to significant exposure to harmful gases or particles, such as smoking. 

Control inhaler: Also known as long-term control, maintenance, or preventer inhalers, this form of medication, which is taken daily, usually contains a steroid that reduces inflammation.

Dry powder inhaler (DPI): A device that delivers asthma medication in a very fine powder that can be inhaled with a deep, strong breath.

Eosinophilic asthma (e-asthma): Type of asthma in which an abnormal increase in eosinophils (a type of blood cell) causes inflammation in the airways; pronounced EE-oh-SIN-oh-FIL-ik.

Family history: Your family’s health history.

Fractional exhaled nitric oxide (FeNO) testing: A test that helps your health-care provider determine how much inflammation you have in your airways by measuring the amount of nitric oxide (NO) you exhale. Higher NO levels may indicate swelling of the airways in your lungs.

Gastroesophageal reflux disease (GERD): A digestive-tract disease caused by stomach acids or foods coming up into the esophagus. Eventually the acids reach the throat and airways, causing a burning sensation (heartburn) in the chest.

Heterogeneity: Variability or diverseness; in terms of asthma, this refers to each person’s individual biological reactions to asthma.

High-efficiency particulate air (HEPA): A HEPA filter can remove at least 99.97% of dust, pollen, and other airborne particles as small as 0.3 microns.

Immunoglobulin E (IgE): IgE is normally found in small amounts in the body, but levels sometimes can increase dramatically when exposed to the allergens that trigger a reaction in your body. IgE can also stimulate other cells to behave in ways that increase inflammation.

Interleukin 4(IL-4) IL-4 signals other cells to begin production of inflammatory substances, sends eosinophils to the inflammatory areas, and causes the smooth muscles around the airway to contract. 

Interleukin 5 (IL-5): IL-5 activates eosinophils and directs them to circulate to the sites of inflammation.  

Thymic stromal lymphopoyetin (TSLP): TSLP activates different cells that stimulate an allergic response in the lungs, which increases eosinophil levels and leads to smooth muscle contraction. 

Inflammation: Swelling and thickening of the airways; a hallmark of asthma.

Long-acting muscarinic antagonist (LAMA): A type of medication that reduces mucus in and widens airways.

Lifestyle and behavior changes: Steps your doctor may recommend to reduce your exposure to asthma triggers, such as staying indoors when the outdoor air quality is poor, or losing weight.

Metered-dose inhaler (MDI): A pressurized device that releases medication in a fine spray for you to inhale.

Methacholine challenge: A test your health-care provider administers to help determine if you have asthma.

Nebulizer: A machine that turns liquid medicine into a mist that can be inhaled slowly through a mask or mouthpiece.

Nonallergic asthma: A type of asthma that can be triggered by a variety of causes not related to an allergic reaction; often begins in adulthood.

Non–type 2 inflammation: An asthma category that includes all types of asthma not caused by eosinophilic or allergic inflammation.

Phenotype: Observable traits or characteristics that are the result of how your genes interact with your environment.

Physical examination: Your asthma specialist will listen to your lungs and check your ears, nose, throat, and eyes for indications of allergy, such as inflammation. They also will examine your skin for eczema (atopic dermatitis).

Priming: Releasing one or more sprays from your inhaler into the air to help ensure the dose you inhale has the right amount of medication.

Rescue inhaler: Also known as quick-relief inhalers, this type of treatment contains a bronchodilator that rapidly widens your airways, providing quick, short-term relief during a flare-up (asthma attack).

Single maintenance and reliever therapy (SMART) inhaler: A type of inhaled medicine that acts as both a rescue inhaler (because it is fast acting) and a control inhaler (because it is long lasting).

Spacer: A device that attaches to your inhaler; it improves the delivery of inhaled medication to the lower airways.

Spirometer: A handheld device with a tube you blow into that helps your health-care provider determine your lung capacity.

Spirometry: A lung function test of how much air you can move in and out of your lungs and how fast you can do it.

Sulfite: A type of preservative found in some foods (eg, beer, wine, shrimp, processed potatoes) that can trigger an allergic asthma response.

Targeted therapy: Treatment tailored to your individual physical response.

Thymic stromal lymphopoietin (TSLP/IL-33): TSLP activates different cells that stimulate an allergic response in the lungs, which increases eosinophil levels and leads to smooth muscle contraction.

Type 2 inflammation: An asthma category that includes all forms of asthma that are driven by eosinophilic or allergic inflammation.

Valved holding chamber (VHC): A type of spacer that is one-way, allowing the patient to breathe air in only from the chamber, not out into the chamber.

Zone: Your Asthma Action Plan outlines treatment according to colored zones: green zone means you are doing well, yellow zone means your asthma is getting worse, and red zone means you need immediate medical attention.