Asthma: Symptoms, Triggers, and the Tests That Guide Treatment

Asthma is a common, long-term lung condition in which the airways become inflamed, swollen, and quick to react, which makes breathing harder at times. It affects about 1 in 13 people in the United States, according to the Centers for Disease Control and Prevention, and it reaches young children and older adults alike. The reassuring news is that, for most people, asthma can be well controlled with the right plan. Modern care increasingly relies on simple blood and breath tests that reveal the kind of inflammation behind your symptoms. In this article you’ll learn what asthma is, the symptoms and triggers to watch for, how doctors diagnose it, and which treatments — from everyday inhalers to newer targeted injections — are used today. You’ll also see how biomarkers such as blood eosinophils, IgE, and exhaled nitric oxide help personalize treatment.

What is asthma?

Asthma is a chronic disease of the bronchial tubes, the branching airways that carry air in and out of your lungs. In asthma, the lining of these airways stays mildly inflamed even between symptoms. When something irritates them, three things tend to happen at once: the airway walls swell, the muscles around them tighten, and the airways produce extra mucus. Together these narrow the passage for air and cause the familiar feeling of not being able to breathe freely.

A key feature of asthma is that this narrowing is usually reversible. Airways can open up again on their own or with medication, which is part of what separates asthma from some other lung diseases. Symptoms often come and go, and many people have long stretches with few or no problems, especially when their condition is well managed.

Why the airways overreact

In people with asthma, the immune system treats harmless things — pollen, dust, or cold air — as threats. This overreaction keeps the airways sensitive, a state doctors call bronchial hyperresponsiveness. The underlying inflammation is the real target of long-term treatment, which is why calming it matters more than simply relieving symptoms as they appear.

Asthma symptoms and warning signs

Asthma symptoms vary from person to person and can change over time. The four most common are wheezing (a whistling sound when breathing out), a cough that is often worse at night or in the early morning, shortness of breath, and a feeling of tightness or pressure in the chest. Some people mainly cough; others notice symptoms only during exercise or a cold.

What an asthma attack feels like

An asthma attack, or flare-up, is a rapid worsening of symptoms as the airways narrow further. Breathing becomes fast and difficult, the cough or wheeze intensifies, and a rescue inhaler brings less relief than usual. Severe attacks are a medical emergency. Breathlessness can also have causes that have nothing to do with the lungs; for one example, you can read our guide to shortness of breath after eating.

What triggers asthma? Causes and risk factors

Asthma does not have a single cause. It develops from a mix of genes and environment, and symptoms are then set off by triggers that differ for each person. Identifying your own triggers is one of the most useful steps in keeping asthma under control.

Veelvoorkomende triggers

• Allergens such as dust mites, pollen, mold, and pet dander
• Respiratory infections, including colds and the flu
• Irritants like tobacco smoke, air pollution, strong odors, and cold, dry air
• Exercise, especially in cold weather
• Strong emotions, stress, and even laughter
• Certain medications and, for some people, workplace dust or chemicals

Respiratory infections deserve special attention because they are among the most frequent triggers of flare-ups. So before each cold-and-flu season, it helps to review our guide to influenza and its complications.

Who is more likely to develop asthma

Risk factors include a family history of asthma or allergies, having other allergic conditions such as eczema or hay fever, exposure to smoke, obesity, and early-life respiratory infections. Many people with asthma also have ongoing nasal and sinus trouble, and you can read our guide to sinus infections to understand that connection.

Understanding type 2 inflammation in plain language

Doctors increasingly describe asthma by the type of inflammation driving it. The most common pattern is called type 2 inflammation (sometimes written “T2-high”). In simple terms, this is an allergic-style immune response in which the body makes extra amounts of certain white blood cells and signaling proteins that inflame the airways.

Two players are central to this process. The first is a white blood cell called the eosinophil, which gathers in the airways and fuels swelling; you can read our full guide to eosinophils and what they reveal in your blood work. The second is immunoglobulin E, or IgE, the antibody that drives allergic reactions. IgE is part of a wider family of antibody proteins, and you can read our overview of the antibody proteins called gamma globulins. Because these markers can be measured, they give doctors a window into what is happening inside your airways without needing to look directly.

Not all asthma is type 2. Some people have “type 2-low” asthma, where other cells such as neutrophils play a larger role; you can read our guide to neutrophils in your blood test to see how that white blood cell differs. Another allergy-linked white cell is covered in our guide to basophils and allergic responses. Knowing which pattern you have increasingly shapes which treatment is chosen.

How asthma is diagnosed: from spirometry to biomarkers

There is no single test for asthma. A diagnosis combines your medical history, a physical exam, and breathing tests, sometimes supported by blood and breath biomarkers that reveal the underlying inflammation.

Lung function tests

The main breathing test is spirometry, a simple, painless measure of how much air you can breathe out and how fast. Doctors often repeat it after a bronchodilator (a medicine that relaxes the airways) to see whether your airflow improves — an important clue for asthma. A related at-home tool, the peak flow meter, tracks day-to-day changes in your breathing.

Blood and breath biomarkers

Biomarkers add another layer. A blood eosinophil count, part of a routine complete blood count, shows how much allergic-type inflammation is present; you can review what a full blood panel includes to see where this fits. Total IgE and allergen-specific IgE reveal an allergic tendency and can pinpoint specific triggers. A newer breath test, FeNO, measures a gas that rises when the airways carry type 2 inflammation. In its 2020 focused updates to the U.S. asthma guidelines, the National Heart, Lung, and Blood Institute recognized FeNO testing as a useful addition in certain situations. For context, you can also read our guide to the inflammation marker CRP — though CRP is a general marker and is not specific to asthma.

If you are unsure which blood work you received, you can compare the two common blood tests known as the CBC and CMP. The table below summarizes the tests most often used to understand the inflammation behind asthma.

How asthma is treated and controlled

Asthma treatment has two goals: relieve symptoms quickly when they occur and, more importantly, calm the underlying inflammation so flare-ups become rare. Most people use inhalers, which deliver medicine straight to the airways with few whole-body effects.

Reliever and controller inhalers

Quick-relief (rescue) inhalers contain a bronchodilator that opens tight airways within minutes during symptoms or an attack. Controller inhalers, usually containing an inhaled corticosteroid, are taken regularly to reduce inflammation over time. Current guidelines increasingly favor inhalers that combine an anti-inflammatory medicine with a reliever, rather than relying on a reliever alone. Using the correct inhaler technique, often with a spacer, makes a real difference in how well the medicine works.

When biologics are considered

A minority of people have severe asthma that stays uncontrolled despite correct inhaler use. For many of them, the driver is type 2 inflammation — and this is where biologics come in. A biologic is a lab-made antibody, given by injection, that blocks one specific molecule fueling inflammation. Approved options target IgE (omalizumab), the signaling protein interleukin-5 or its receptor (mepolizumab and benralizumab), and the interleukin-4 and interleukin-13 pathway (dupilumab). Doctors choose among them using your biomarkers, especially blood eosinophils and IgE, which is why testing matters so much. Specialist bodies such as the American Academy of Allergy, Asthma & Immunology publish patient guidance on these treatments, which are always prescribed and monitored by a specialist.

Living with asthma day to day

Most people with asthma lead full, active lives. The key is a written asthma action plan, agreed with your doctor, that tells you which medicines to take daily, how to spot worsening control, and exactly what to do during an attack.

Everyday self-management

• Take your controller medicine every day, even when you feel well
• Learn and avoid your personal triggers
• Keep your rescue inhaler with you at all times
• Check your inhaler technique with a pharmacist or nurse
• Keep vaccinations up to date, since infections can trigger flare-ups
• Attend regular reviews so your treatment can be adjusted

Wanneer moet u spoedeisende medische hulp zoeken?

Call emergency services or go to the nearest emergency department if you or someone else has any of these signs of a severe asthma attack:

• Severe breathlessness, or being too short of breath to speak in full sentences
• A rescue inhaler that does not help, or that is needed again within a few hours
• Lips or fingertips turning blue or gray
• Fast breathing with the chest or ribs pulling in, especially in a child
• Drowsiness, confusion, or unusual exhaustion

Make a routine, non-urgent appointment if you use your rescue inhaler more than twice a week, wake at night with symptoms, or find asthma limiting your activities — all signs that your control could be better.

Recente wetenschappelijke ontwikkelingen

Research over the past few years has made asthma care more precise, especially for people with type 2 inflammation. Here are some findings translated into plain language.

A large 2025 analysis pooled the control groups of 22 clinical trials — a meta-analysis, meaning a study that combines many earlier studies — and confirmed that two simple markers help predict who is most likely to have an asthma attack: the number of eosinophils in the blood and the level of nitric oxide in the breath (FeNO). The risk was highest when both were raised together. What this means for you: these quick, low-effort tests can flag higher risk early, so your treatment can be strengthened before an attack happens. The researchers rated this evidence as high quality.

A 2024 health-technology assessment reviewed how well the FeNO breath test performs. It concluded that adding FeNO to standard testing improves the accuracy of an asthma diagnosis and, when used to guide treatment, likely reduces flare-ups and the need for oral steroids. What this means for you: a simple breath test may help confirm asthma and keep it steadier, although it is used alongside other tests rather than on its own.

Doctors now sort asthma into patterns, or phenotypes, using a panel of markers — blood eosinophils, total and allergen-specific IgE, and FeNO. A 2025 review described how this “type 2-high versus type 2-low” approach helps match each person to the treatment most likely to work. What this means for you: your biomarker results are not just numbers; they help shape a plan tailored to your form of asthma.

For severe asthma that requires daily steroid tablets, a 2024 pooled analysis of seven randomized trials found that three biologic injections — benralizumab, dupilumab, and mepolizumab — helped people lower or stop their steroid tablets while keeping asthma controlled. What this means for you: if you have severe type 2 asthma, targeted injections may reduce your reliance on oral steroids and their side effects. These are specialist treatments, chosen with your biomarkers in mind.

Reviews of severe asthma now describe an ambitious goal called clinical remission — long stretches with no attacks, stable breathing, and few symptoms — made more achievable by matching the right biologic to each person’s biomarkers. What this means for you: even severe asthma is increasingly manageable with a personalized, test-guided plan, decided together with your medical team.

Glossarium

Veelgestelde vragen

Is asthma hereditary?

Asthma is not passed down in a simple way, but genes do play a role. Having a parent or sibling with asthma, or having allergic conditions such as eczema or hay fever, raises your chances. Genes work together with the environment, so inheriting a tendency does not guarantee you will develop asthma. Early-life exposures, infections, and allergens all influence whether it appears.

Can you exercise with asthma?

Yes. Most people with well-controlled asthma can and should stay active, and many athletes have asthma. Some people notice symptoms during exercise, especially in cold, dry air. Warming up, breathing through the nose, and using a rescue inhaler before activity when advised by your doctor can help. If exercise regularly brings on symptoms, it often signals that your day-to-day control needs reviewing.

Does asthma go away with age?

Asthma can change over a lifetime. Some children see their symptoms fade during their teens, though the underlying tendency can remain and return later. In adults, asthma is usually a long-term condition that is managed rather than cured. The good news is that with the right treatment and follow-up, most people keep their symptoms under control for years at a time.

What is the difference between allergic and eosinophilic asthma?

They overlap. Allergic asthma is triggered by specific allergens and is linked to the IgE antibody. Eosinophilic asthma is defined by a high number of eosinophils, a white blood cell tied to type 2 inflammation. A person can have both features at once. Doctors use blood tests and, sometimes, FeNO to tell which pattern is present, because it guides treatment choices.

Can a blood test diagnose asthma?

Not on its own. No single blood test confirms asthma. Diagnosis rests mainly on your symptoms and breathing tests such as spirometry. Blood markers like the eosinophil count and IgE, along with the FeNO breath test, add valuable information about the type of inflammation and help personalize treatment. They support the diagnosis and management rather than replace the clinical assessment.

Is asthma curable?

There is no cure for asthma yet, but it is highly treatable. With a daily controller medicine, trigger awareness, and a clear action plan, most people reach good control, meaning few symptoms and rare flare-ups. For severe asthma, newer biologic treatments can dramatically reduce attacks. The aim of modern care is long-lasting control and, increasingly, long symptom-free periods.

Bronnen

• Centers for Disease Control and Prevention — Asthma — https://www.cdc.gov/asthma/index.html
• National Heart, Lung, and Blood Institute (NHLBI) — Asthma — https://www.nhlbi.nih.gov/health/asthma
• American Academy of Allergy, Asthma & Immunology (AAAAI) — Asthma: Symptoms, Diagnosis, Management & Treatment — https://www.aaaai.org/conditions-treatments/asthma
• Meulmeester FL, et al. — Inflammatory and clinical risk factors for asthma attacks (ORACLE2): a patient-level meta-analysis of control groups of 22 randomised trials — The Lancet Respiratory Medicine, 2025 — https://doi.org/10.1016/S2213-2600(25)00037-2
• Ontario Health (Quality) — Fractional Exhaled Nitric Oxide Testing for the Diagnosis and Management of Asthma: a Health Technology Assessment — Ontario Health Technology Assessment Series, 2024 — https://pmc.ncbi.nlm.nih.gov/articles/PMC11423898/
• Grunwell JR, Fitzpatrick AM — Asthma Phenotypes and Biomarkers — Respiratory Care, 2025 — https://doi.org/10.1089/respcare.12352
• Phinyo P, et al. — Efficacy and Safety of Biologics for Oral Corticosteroid-Dependent Asthma: A Systematic Review and Network Meta-Analysis — The Journal of Allergy and Clinical Immunology: In Practice, 2024 — https://doi.org/10.1016/j.jaip.2023.11.007
• Pelaia C, et al. — Type 2 severe asthma: pathophysiology and treatment with biologics — Expert Review of Respiratory Medicine, 2024 — https://doi.org/10.1080/17476348.2024.2380072

Verder lezen

• Eosinofielen: alles over deze belangrijke bloedcellen
• Gids voor volledig bloedonderzoek: wat zit er in een compleet bloedpanel
• Immunoglobulin G (IgG): understanding your blood test
• Serum tryptase: understanding this allergy-related blood test
• Sinus infection: symptoms, causes, and treatments

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If you have asthma, your blood and breath tests hold useful clues about the inflammation behind your symptoms. AI DiagMe helps you make sense of results such as your blood eosinophil count, total and allergen-specific IgE, and a complete blood count, explaining what each value means in plain language. It is a tool to help you understand your results and prepare better questions for your appointment — it does not provide a diagnosis and does not replace your doctor.