Asthma: Overview

Asthma is a chronic lung disease that involves inflammation and narrowing of the airways. This results in symptoms such as wheezing, coughing and shortness of breath. Asthma can affect anyone of any age and the severity of symptoms varies greatly amongst individuals.

Not everyone who presents with symptoms of asthma will actually end up with a diagnosis of asthma because there are other conditions that may have some or all of the same symptoms, so it is important to see a medical professional for a complete check-up.

There is no cure for asthma but proper diagnosis and management of the condition can allow for normal activity and quality of life for many individuals.

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Back to: « Asthma

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Asthma is a disease that affects your lungs. It causes repeated episodes of wheezing, breathlessness, chest tightness, and nighttime or early morning coughing. Asthma can be controlled by taking medicine and avoiding the triggers that can cause an attack. You must also remove the triggers in your environment that can make your asthma worse.

Source: CDC1

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What Is Asthma?

Asthma (AZ-ma) is a chronic (long-term) lung disease that inflames and narrows the airways. Asthma causes recurring periods of wheezing (a whistling sound when you breathe), chest tightness, shortness of breath, and coughing. The coughing often occurs at night or early in the morning.

Asthma affects people of all ages, but it most often starts during childhood. In the United States, more than 25 million people are known to have asthma. About 7 million of these people are children.

Overview

To understand asthma, it helps to know how the airways work. The airways are tubes that carry air into and out of your lungs. People who have asthma have inflamed airways. The inflammation makes the airways swollen and very sensitive. The airways tend to react strongly to certain inhaled substances.

When the airways react, the muscles around them tighten. This narrows the airways, causing less air to flow into the lungs. The swelling also can worsen, making the airways even narrower. Cells in the airways might make more mucus than usual. Mucus is a sticky, thick liquid that can further narrow the airways.

This chain reaction can result in asthma symptoms. Symptoms can happen each time the airways are inflamed.

Asthma

Sometimes asthma symptoms are mild and go away on their own or after minimal treatment with asthma medicine. Other times, symptoms continue to get worse.

When symptoms get more intense and/or more symptoms occur, you're having an asthma attack. Asthma attacks also are called flareups or exacerbations (eg-zas-er-BA-shuns).

Treating symptoms when you first notice them is important. This will help prevent the symptoms from worsening and causing a severe asthma attack. Severe asthma attacks may require emergency care, and they can be fatal.

Outlook

Asthma has no cure. Even when you feel fine, you still have the disease and it can flare up at any time.

However, with today's knowledge and treatments, most people who have asthma are able to manage the disease. They have few, if any, symptoms. They can live normal, active lives and sleep through the night without interruption from asthma.

If you have asthma, you can take an active role in managing the disease. For successful, thorough, and ongoing treatment, build strong partnerships with your doctor and other health care providers.

Source: NHLBI (NIH)2

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Since 1971, NIAID has supported targeted research to understand the causes of and develop preventions and treatments for asthma, a respiratory disease that affects approximately 25 million Americans, including 7 million children aged 17 years and under. NIAID research focuses on understanding how the environment, allergens, and genetics interact with the body's immune system to cause the disease and aggravate the symptoms.

Source: NIAID (NIH)3

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Asthma Facts

Asthma is a severe and chronic disease that affects over 230 million people worldwide, including more than 18 million adults and 7 million children in the United States.

According to the Centers for Disease Control and Prevention, there were 1.9 million emergency department visits and 479,300 hospitalizations for asthma in 2009. More than 14 million work days were lost to asthma in 2008, and the direct and indirect costs of asthma to the U.S. economy average $56 billion each year.

Asthma is one of the leading chronic childhood diseases, a major cause of childhood disability, and places a huge burden on affected children and their families, limiting the child's ability to learn, play, and even sleep. Children missed 10.5 million school days in 2008 because of asthma.

Approximately 16 percent of African-American children have asthma, compared to 8.2 percent of white children. In addition, African-American children are twice as likely as white children to be hospitalized for asthma and four times as likely to die of the disease.

The cause of asthma remains unknown. Through research programs and the efforts of hundreds of independent researchers, NIAID is working to understand the underlying causes of asthma and reduce the burden of this disease.?

Source: NIAID (NIH)4

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What is asthma?

Asthma is an inflammatory disease of the lung. This inflammatory process can occur along the entire airway from the nose to the lung. Once the airway becomes swollen and inflamed, it becomes narrower, and less air gets through to the lung tissue. This causes symptoms like wheezing, coughing, chest tightness, and trouble breathing. During an asthma attack, the muscles around the airways tighten up and the asthma symptoms become even worse than usual.

Once considered a minor ailment, asthma is now the most common chronic disorder in childhood. The prevalence of asthma has progressively increased over the past 15 years. In the United States alone, nearly 40 million people — 13.3 percent of adults and 13.8 percent of children — have been diagnosed with asthma.

Source: NIEHS (NIH)5

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Asthma is a chronic disease that affects your airways. Your airways are tubes that carry air in and out of your lungs. If you have asthma, the inside walls of your airways become sore and swollen. That makes them very sensitive, and they may react strongly to things that you are allergic to or find irritating. When your airways react, they get narrower and your lungs get less air.

Symptoms of asthma include

Not all people who have asthma have these symptoms. Having these symptoms doesn't always mean that you have asthma. Your doctor will diagnose asthma based on lung function tests, your medical history, and a physical exam. You may also have allergy tests.

When your asthma symptoms become worse than usual, it's called an asthma attack. Severe asthma attacks may require emergency care, and they can be fatal.

Asthma is treated with two kinds of medicines: quick-relief medicines to stop asthma symptoms and long-term control medicines to prevent symptoms.

NIH: National Heart, Lung, and Blood Institute

Source: MedLinePlus (NIH)6

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Asthma is a chronic disease that affects your airways. Your airways are tubes that carry air in and out of your lungs. If you have asthma, the inside walls of your airways become sore and swollen.

In the United States, about 20 million people have asthma. Nearly 9 million of them are children. Children have smaller airways than adults, which makes asthma especially serious for them. Children with asthma may experience wheezing, coughing, chest tightness, and trouble breathing, especially early in the morning or at night.

Many things can cause asthma, including

When asthma symptoms become worse than usual, it is called an asthma attack. Asthma is treated with two kinds of medicines: quick-relief medicines to stop asthma symptoms and long-term control medicines to prevent symptoms.

Source: MedLinePlus (NIH)7

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Asthma is a breathing disorder characterized by inflammation of the airways and recurrent episodes of breathing difficulty. These episodes, sometimes referred to as asthma attacks, are triggered by irritation of the inflamed airways. In allergic asthma, the attacks occur when substances known as allergens are inhaled, causing an allergic reaction. Allergens are harmless substances that the body's immune system mistakenly reacts to as though they are harmful. Common allergens include pollen, dust, animal dander, and mold. The immune response leads to the symptoms of asthma. Allergic asthma is the most common form of the disorder.

A hallmark of asthma is bronchial hyperresponsiveness, which means the airways are especially sensitive to irritants and respond excessively. Because of this hyperresponsiveness, attacks can be triggered by irritants other than allergens, such as physical activity, respiratory infections, or exposure to tobacco smoke, in people with allergic asthma.

An asthma attack is characterized by tightening of the muscles around the airways (bronchoconstriction), which narrows the airway and makes breathing difficult. Additionally, the immune reaction can lead to swelling of the airways and overproduction of mucus. During an attack, an affected individual can experience chest tightness, wheezing, shortness of breath, and coughing. Over time, the muscles around the airways can become enlarged (hypertrophied), further narrowing the airways.

Some people with allergic asthma have another allergic disorder, such as hay fever (allergic rhinitis) or food allergies. Asthma is sometimes part of a series of allergic disorders, referred to as the atopic march. Development of these conditions typically follows a pattern, beginning with eczema (atopic dermatitis), followed by food allergies, then hay fever, and finally asthma. However, not all individuals with asthma have progressed through the atopic march, and not all individuals with one allergic disease will develop others.

Source: GHR (NLM/NIH)8

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Asthma is a chronic inflammatory disorder of the airways characterized by episodes of reversible breathing problems due to airway narrowing and obstruction. These episodes can range in severity from mild to life threatening. Symptoms of asthma include wheezing, coughing, chest tightness, and shortness of breath. Daily preventive treatment can prevent symptoms and attacks and enable individuals who have asthma to lead active lives.

Source: Healthy People (DHHS)9

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Asthma affects more than 5% of the population of the US, including children. It is a chronic inflammatory disorder of the airways characterized by coughing, shortness of breath, and chest tightness. A variety of "triggers" may initiate or worsen an asthma attack, including viral respiratory infections, exercise, and exposure to irritants such as tobacco smoke. The physiological symptoms of asthma are a narrowing of the airways caused by edema (fluid in the intracellular tissue space) and the influx of inflammatory cells into the walls of the airways.

Asthma is a what is known as a "complex" heritable disease. This means that there are a number of genes that contribute toward a person's susceptibility to a disease, and in the case of asthma, chromosomes 5, 6, 11, 14, and 12 have all been implicated. The relative roles of these genes in asthma predisposition are not clear, but one of the most promising sites for investigation is on chromosome 5. Although a gene for asthma from this site has not yet been specifically identified, it is known that this region is rich in genes coding for key molecules in the inflammatory response seen in asthma, including cytokines, growth factors, and growth factor receptors.

The search for specific asthma genes is ongoing. Assisting in this international human effort are model organisms such as mice, which have similar chromosomal architecture to our chromosome 5 site on their chromosomes 11, 13, and 18. Further study of the genes in these areas (and others) of the human genome will implicate specific genes involved in asthma and perhaps also suggest related biological pathways that play a role in the pathogenesis of asthma.

Source: NCBI, Genes and Disease (NCBI/NIH)10

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Most people have little trouble climbing a flight of stairs or taking a brisk walk, but these simple activities can be tough for someone with asthma. Although there’s no cure, you can breathe easier by knowing how to keep the condition under control.

Asthma is a common, long-lasting disease that affects the lungs. It can begin in childhood or adulthood. More than 25 million Americans have asthma, including 7 million children. Without proper care, asthma can become serious, even deadly. But most people with asthma learn to manage the disease so they have few symptoms or none at all.

Source: NIH News in Health (NIH)11

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Asthma is caused by swelling and inflammation of your airways. When the airways narrow, less air gets through to your lungs, causing wheezing, coughing, chest tightness and trouble breathing.

Source: NIH News in Health (NIH)12

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You probably know of at least one child with severe asthma. It’s just more common these days. Once considered a minor ailment affecting only a few, asthma is now the most common chronic disorder in childhood, affecting an estimated 6.2 million children under the age of 18. The trend has been particularly disturbing among inner-city children. Research is now uncovering the complex mix of genes and environmental factors that cause the disease.

Source: NIH News in Health (NIH)13

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More than 20 million Americans have asthma. Mild persistent asthma brings symptoms like wheezing, coughing, or chest tightness more than twice a week but not daily, or wakes you up more than two nights a month.

Source: NIH News in Health (NIH)14

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Asthma: A disorder causing the airways to become inflamed and narrowed due to mucous production and leads to symptoms of wheezing, shortness of breath, coughing and chest tightness in response to stimuli that would not cause reactions in healthy individuals. Asthma can be triggered by an inhaled allergen.

Source: RDCRN (NCATS/NIH)15

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Asthma: A lung disease characterized by narrowing of the respiratory airways. Symptoms include recurrent attacks of wheezing, coughing, shortness of breath (dyspnea).

Source: RDCRN (NCATS/NIH)16

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Asthma is one of the most common lifelong chronic diseases. There are 24 million Americans living with asthma, a disease affecting the lungs, causing repeated episodes of wheezing, breathlessness, chest tightness, and coughing.

Source: CDC Features17

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Summary

Asthma is a breathing disorder that affects the airways. People with this condition experience recurrent swelling and narrowing of the airways of the lungs which is associated with wheezing, shortness of breath, chest tightness, and coughing. Most affected people have episodes of symptoms ("asthma attacks") followed by symptom-free periods; however, some may experience persistent shortness of breath in between attacks.[1, 2] Asthma is considered a complex or multifactorial condition that is likely due to a combination of multiple genetic, environmental, and lifestyle factors. Many people with asthma have a personal or family history of allergies, such as hay fever or eczema. Having a family member with asthma is associated with an increased risk of developing the condition.[3] Treatment generally includes various medications, both to prevent asthma attacks and to provide quick relief during an attack.[1, 2] Last updated: 2/28/2016

Source: GARD (NIH)18

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Summary

Asthma is a chronic disease that affects your airways. Your airways are tubes that carry air in and out of your lungs. If you have asthma, the inside walls of your airways become sore and swollen. That makes them very sensitive, and they may react strongly to things that you are allergic to or find irritating. When your airways react, they get narrower and your lungs get less air. Symptoms of asthma include. -Wheezing. -Coughing, especially early in the morning or at night. -Chest tightness. -Shortness of breath. Not all people who have asthma have these symptoms. Having these symptoms doesn't always mean that you have asthma. Your doctor will diagnose asthma based on lung function tests, your medical history, and a physical exam. You may also have allergy tests. When your asthma symptoms become worse than usual, it's called an asthma attack. Severe asthma attacks may require emergency care, and they can be fatal. Asthma is treated with two kinds of medicines: quick-relief medicines to stop asthma symptoms and long-term control medicines to prevent symptoms. . NIH: National Heart, Lung, and Blood Institute. [from MedlinePlus]

Source: GTR (NCBI/NIH)19

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Asthma is a disorder affecting the airways of the lungs. People with asthma have very sensitive airways that narrow in response to certain "triggers", leading to difficulty in breathing. The airway narrowing is caused by inflammation and swelling of the airway lining, the tightening of the airway muscles, and the production of excess mucus. This results in a reduced airflow in and out of the lungs.

Source: Queensland Health20

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Asthma is a disorder affecting the airways of the lungs. People with asthma have very sensitive airways that narrow in response to certain "triggers", leading to difficulty in breathing. The airway narrowing is caused by inflammation and swelling of the airway lining, the tightening of the airway muscles, and the production of excess mucus. This results in a reduced airflow in and out of the lungs.

Source: Queensland Health21

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asthma: A common, chronic inflammatory disease of the air passages that presents as episodes of wheezing, breathlessness and chest tightness due to widespread narrowing of the airways and obstruction of airflow.

Source: Australian Institute of Health and Welfare22

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Asthma is a chronic inflammatory disorder of the airways. People with asthma experience episodes of wheezing, breathlessness and chest tightness due to widespread narrowing of the airways.

Source: Australian Institute of Health and Welfare23

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What is asthma?

Asthma is an inflammatory disease of the lung. It can occur along the entire airway from the nose to the lung. Once the airway becomes swollen and inflamed, it becomes narrower, and less air gets through to the lung tissue. The exact cause of asthma is not known. Researchers think some genetic and environmental factors interact to cause asthma, usually before the age of 5.

Source: MedLinePlus Magazine (NIH)24

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Asthma is a lung disease that narrows or blocks the airways. This causes wheezing, shortness of breath, coughing, and other breathing difficulties. Asthma attacks can be triggered by viral infections, cold air, exercise, anxiety, allergens, and other factors. Almost 80 percent of people with asthma have allergies, but we do not know to what extent the allergies trigger the breathing problems. However, some people are diagnosed with allergic asthma because the problem is set off primarily by an immune response to one or more specific allergens. Most of the time, the culprit allergens are those found indoors, such as pets, house dust mites, cockroaches, and mold. Increased pollen and mold levels have also been associated with worsening asthma.

Source: MedLinePlus Magazine (NIH)25

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Asthma is a lung disease that inflames and narrows the airways, causing wheezing, chest tightness, shortness of breath, and coughing. It starts mostly in childhood but affects all age groups. Asthma is a chronic—long-term—disease.

Source: MedLinePlus Magazine (NIH)26

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An asthma attack makes it hard to breath. Find out about managing asthma, asthma medication, treating asthma attacks, and more.

Source: New Zealand Health27

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Asthma is a common lung condition that causes occasional breathing difficulties.

It affects people of all ages and often starts in childhood, although it can also develop for the first time in adults.

There's currently no cure, but there are simple treatments that can help keep the symptoms under control so it doesn't have a big impact on your life.

Source: NHS Choices UK28

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Asthma: A chronic respiratory disease manifested as difficulty breathing due to the narrowing of bronchial passageways.29

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Asthma: A form of bronchial disorder with three distinct components: airway hyper-responsiveness (Respiratory Hypersensitivity), airway Inflammation, and intermittent Airway Obstruction. It is characterized by spasmodic contraction of airway smooth muscle, Wheezing, and dyspnea (Dyspnea, Paroxysmal).30

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Asthma is characterized by increased responsiveness of the tracheobronchial tree to multiple stimuli, leading to narrowing of the air passages with resultant dyspnea, cough, and wheezing.31

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Asthma: A bronchial disease that is characterized by chronic inflammation and narrowing of the airways, which is caused by a combination of environmental and genetic factors. The disease has symptom recurring periods of wheezing (a whistling sound while breathing), has symptom chest tightness, has symptom shortness of breath, has symptom mucus production and has symptom coughing. The symptoms appear due to a variety of triggers such as allergens, irritants, respiratory infections, weather changes, exercise, stress, reflux disease, medications, foods and emotional anxiety.32

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Asthma: A respiratory system adverse event which has an outcome of asthma33

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Asthma: A bronchial disease that is characterized by chronic inflammation and narrowing of the airways, which is caused by a combination of environmental and genetic factors. The disease has symptom recurring periods of wheezing (a whistling sound while breathing), has symptom chest tightness, has symptom shortness of breath, has symptom mucus production and has symptom coughing. The symptoms appear due to a variety of triggers such as allergens, irritants, respiratory infections, weather changes, exercise, stress, reflux disease, medications, foods and emotional anxiety.34

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Fast Facts

  • Asthma is a chronic (long-term) lung disease that inflames and narrows the airways. The exact cause is unknown. There is no cure.
  • Asthma most often starts during childhood. Of the 24.6 million Americans affected, nearly seven million are children.
  • Asthma causes wheezing, chest tightness, shortness of breath, and coughing.
  • It's important to treat asthma symptoms when you first notice them. This helps prevent them from worsening and causing severe attacks that may require emergency care, and can be fatal.
  • Allergens, pollutants, and irritants can bring on symptoms. So can exercise, but do not avoid it. Physical activity is important for health. Discuss with your health professional asthma medicines that can help you stay active.
  • Most people who have asthma are able to manage the disease. They have few, if any, symptoms and can live normal, active lives.

Source: MedLinePlus Magazine (NIH)35

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References

  1. Source: CDC: cdc.gov/ asthma/ 
  2. Source: NHLBI (NIH): nhlbi.nih.gov/ health/ health-topics/ topics/ asthma
  3. Source: NIAID (NIH): niaid.nih.gov/ topics/ asthma/ Pages/ default.aspx
  4. Source: NIAID (NIH): niaid.nih.gov/ topics/ asthma/ understanding/ Pages/ facts.aspx
  5. Source: NIEHS (NIH): niehs.nih.gov/ health/ topics/ conditions/ asthma/ index.cfm
  6. Source: MedLinePlus (NIH): medlineplus.gov/ asthma.html
  7. Source: MedLinePlus (NIH): medlineplus.gov/ asthmainchildren.html
  8. Source: GHR (NLM/NIH): ghr.nlm.nih.gov/ condition/ allergic-asthma
  9. Source: Healthy People (DHHS): healthypeople.gov/ 2020/ topics-objectives/ topic/ respiratory-diseases
  10. Source: NCBI, Genes and Disease (NCBI/NIH): ncbi.nlm.nih.gov/ books/ NBK22181/ 
  11. Source: NIH News in Health (NIH): newsinhealth.nih.gov/ issue/ jun2014/ feature1
  12. Source: NIH News in Health (NIH): newsinhealth.nih.gov/ 2008/ May/ docs/ 01features_02.htm
  13. Source: NIH News in Health (NIH): newsinhealth.nih.gov/ 2006/ July/ docs/ 01features_01.htm
  14. Source: NIH News in Health (NIH): newsinhealth.nih.gov/ 2005/ June2005/ docs/ 02capsules.htm
  15. Source: RDCRN (NCATS/NIH): rarediseasesnetwork.org/ cms/ cegir/ Learn-More/ Glossary
  16. Source: RDCRN (NCATS/NIH): rarediseasesnetwork.org/ cms/ rld/ Learn-More/ Glossary
  17. Source: CDC Features: cdc.gov/ features/ AsthmaAwareness/ index.html
  18. Source: GARD (NIH): rarediseases.info.nih.gov/ diseases/ 10246/ asthma
  19. Source: GTR (NCBI/NIH): ncbi.nlm.nih.gov/ gtr/ conditions/ C0004096/ 
  20. Source: Queensland Health: conditions.health.qld.gov.au/ HealthCondition/ condition/ 8/ 29/ 9/ asthma
  21. Source: Queensland Health: conditions.health.qld.gov.au/ HealthCondition/ condition/ 15/ 29/ 9/ asthma
  22. Source: Australian Institute of Health and Welfare: aihw.gov.au/ reports-statistics/ health-welfare-overview/ australias-health/ glossary
  23. Source: Australian Institute of Health and Welfare: aihw.gov.au/ reports-statistics/ health-conditions-disability-deaths/ asthma-other-chronic-respiratory-conditions/ about
  24. Source: MedLinePlus Magazine (NIH): medlineplus.gov/ magazine/ issues/ fall17/ articles/ fall17pg26.html
  25. Source: MedLinePlus Magazine (NIH): medlineplus.gov/ magazine/ issues/ spring15/ articles/ spring15pg26-27.html
  26. Source: MedLinePlus Magazine (NIH): medlineplus.gov/ magazine/ issues/ fall13/ articles/ fall13pg12-13.html
  27. Source: New Zealand Health: health.govt.nz/ your-health/ conditions-and-treatments/ diseases-and-illnesses
  28. Source: NHS Choices UK: nhs.uk/ conditions/ Asthma/ 
  29. Source: NCI Thesaurus
  30. Source: MeSH (U.S. National Library of Medicine)
  31. Source: Human Phenotype Ontology
  32. Source: Disease Ontology
  33. Source: OAE Ontology
  34. Source: Monarch Initiative
  35. Source: MedLinePlus Magazine (NIH): medlineplus.gov/ magazine/ issues/ fall13/ articles/ fall13pg12-13.html

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Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.