Mild Persistent Asthma: Common Symptoms, Causes, Diagnosis, And Treatment

If you have been diagnosed with asthma but do not experience daily symptoms or flare-ups, chances are that you have mild persistent asthma. There are three types of asthma: mild asthma, moderate asthma, and severe asthma.

However, mild asthma can also progress into moderate or severe asthma if not managed properly. That's why some health experts also consider mild asthma to be a stage of the disease, depending on the symptoms displayed. 

Research suggests that 50–75% of asthmatic patients have mild asthma.¹ Although mild asthma remains stable over the long term, it is important to understand its symptoms, causes, and treatment to manage it successfully and prevent exacerbation.

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Medical definition of mild persistent asthma

One recent definition for mild asthma, according to The Global Initiative for Asthma (GINA), is asthma that is well controlled with either Step 1 (short-term inhalers taken when symptoms arise) or Step 2 (daily dose of inhaled corticosteroid (ICS) treatment.²

This definition is based on the level of treatment required to effectively manage asthma. It's important to note that there is no global consensus or standard definition for the different types of asthma. Every country and region adheres to a different definition.

Here in the US, we often use a system developed by the US National Asthma Education and Prevention Program, which is based on a patient's symptoms at diagnosis.³ Your doctor will evaluate your daytime symptoms, nighttime symptoms, the frequency of those symptoms, and lung function.

These symptoms and tests are then used to determine the type and severity of asthma.

Asthma classification: mild, moderate, and severe asthma

Asthma research differentiates between intermittent and persistent asthma.⁴ As a result, we have four types of asthma as follows:

Mild intermittent asthma

  • Daytime symptoms appear twice a week at most

  • Nighttime symptoms occur twice a month at most

  • There are no symptoms between flare-ups

  • A spirometry test returns at least 80% forced expiratory volume (FEV1)

  • A peak flow test shows variability of less than 20%

In a spirometry test, FEV1 of 80% means that you can force out 80% of the air in your lungs within 1 second.  

The peak flow test measures how much air comes out of your lungs when you blow as hard as possible. The results are recorded as peak expiratory flow (PEF) rate. 

PEF variability measures the variation of the rate at which you can force out air from your lungs. Normal peak expiratory flow rate is different for every person, depending on their age, height, sex, and race. 

Mild persistent asthma

  • Daytime symptoms show up more than twice a week, but not daily

  • Nighttime symptoms occur more than twice a month

  • Flare-ups can hinder your physical performance

  • Lung function tests return FEV1 values equal to or above 80% of the normal values

  • Peak flow test shows variability of 20–30% 

Moderate persistent asthma

  • Daytime symptoms occur every day

  • Nighttime symptoms occur at least once a week, but not every night

  • FEV1 values in lung tests are 60–80% of expected values

  • Peak flow test shows variability of more than 30% 

Severe persistent asthma

  • Patients continually experience daytime symptoms and flare-ups

  • Patients have to limit physical activity

  • Nighttime symptoms occur frequently (often 7x per week)

  • Actual FEV1 values are less than 60% of the expected values

  • Peak flow test shows variability of more than 30%  

Asthma can also be classified as allergic or non-allergic, adult-onset or pediatric, exercise-induced asthma, or occupational asthma.

Symptoms of mild asthma

Asthma patients display distinct symptoms, and their severity determines your treatment plan. You can also have temporary asthma flare-ups (attacks or exacerbations) when symptoms become significantly worse.

Some of these symptoms include: 

  • Shortness of breath

  • Wheezing (whistling when you breathe)

  • A buildup of mucus (sputum) in the airways

  • Tightness, pain, or pressure in the chest

These symptoms can occur during the day or night, and physicians are careful to distinguish between the two because frequent nighttime (nocturnal) symptoms could indicate more severe asthma. They can also cause patients to wake up in fits of coughing or breathlessness, reducing the quality of sleep.

Flare-ups when you have mild asthma

Asthma flare-ups occur when your airways become so swollen that your lungs aren't taking in enough oxygen. They can occur on their own but are often triggered by something else, such as allergens or exercise.

Flare-ups often require emergency medical attention. In more severe cases, flare-ups cause difficulty breathing and talking, a fast heartbeat, confusion, drowsiness, and blue lips.

How mild asthma is diagnosed

The doctor will ask you to describe your symptoms when diagnosing asthma. Tell-tale symptoms such as wheezing and shortness of breath can indicate to the physician that further tests are required to confirm the diagnosis.

Such tests include:

  • Examining the upper and lower respiratory tract for wheezing, a runny nose, and swelling and growth in the nasal passages

  • Checking the skin for signs of allergies such as hives or rashes

  • A series of asthma tests, such as:

  • Spirometry, which determines how well you can breathe by measuring the amount of air you can inhale or exhale

  • Peak flow tests, which measure how fast you breathe in and out. Peak flow results below the expected levels indicate that the lungs aren't working normally.

  • Challenge tests to find out how factors such as exercise or cold air influence your breathing

  • Blood tests to check for allergies, especially when diagnosing allergic asthma

These tests are also used to monitor asthma treatment and rule out other respiratory conditions, such as chronic obstructive pulmonary disease (COPD).

Since asthma tends to run in the family, the doctor will also examine your medical history and ask about your family history. The combination of personal and family medical history paired with test results helps the doctor diagnose the type and severity of asthma you have.

If you haven't been formally diagnosed with asthma, it will be helpful if you keep a log of your symptoms and suspected triggers (irritants you come across).

What causes mild persistent asthma?

We don't know what causes asthma, even though studies have linked the disease to various risk factors.⁵ In some cases, these risk factors can be both a cause and a trigger depending on the type of asthma you have. Here are some of those factors:


Allergic asthma is the most common type of disease in which the body becomes particularly sensitive to a specific substance. Your body's immune system causes an allergic response whenever you come into contact with that allergen.

If your asthma is allergic, you will notice that it flares up when you're around the trigger. Common triggers include plant spores, mold spores, pet dander, dust mites, cockroaches, cigarette smoke, air pollution, or even strong chemicals and smells.

Allergic asthma also tends to occur with other allergy-related diseases such as eczema, hay fever, and atopic dermatitis.


Studies show that obesity is a significant risk factor for asthma and a modifying factor in both children and adults.⁶ Patients with obesity have more frequent and severe symptoms. According to data published by the NIH, 11.1% of adults with obesity have asthma compared to 7.1% of adults of normal weight. 

Data presented by the American Academy of Pediatrics suggests that children who are overweight are at a higher risk (8–17%) of developing asthma and that children with obesity are at an even greater risk (26–38%).⁷ In addition, 23–27% of new asthma cases in children can be attributed directly to obesity.


Pregnancy can aggravate asthma symptoms in women. In fact, asthma is the most common chronic condition in pregnant women that complicates 4–8% of pregnancies.⁸ This is largely due to the lack of effective controller therapies during pregnancies, as pregnant women have to stop taking anti-inflammatory drugs in the last stages of pregnancy.


Both first and second-hand tobacco smoke are powerful irritants that can cause and trigger asthma. Tobacco smoke irritates the airways, putting active smokers at a higher risk of contracting asthma. In particular, female smokers have a higher chance (70%) of contracting asthma compared to non-smokers.

Smokers also find it harder to control asthma. Tobacco smoke causes airway inflammation and insensitivity to some anti-inflammatory drugs (corticosteroids). Studies also suggest that parents who smoke can cause asthma in their children, either in infancy or later in life.⁹

Genetic factors

Asthma tends to be genetic, although not all cases of asthma are inherited. Children of asthmatic parents are at an increased risk of developing the disease depending on the closeness of the parental relation. This risk also varies depending on the severity of the disease and whether the parent was affected by the disease at a young age.

The genetic link isn't that simple, though. Even with modern technology, researchers haven't isolated any particular gene responsible for asthma, making predictions difficult. Since asthma is multifactorial, environmental factors such as allergens play an equally important role. 

Intense emotions

Stress, anger, joy, laughter, crying, and other heightened emotions can trigger or increase the severity of asthma symptoms. There is also a link between asthma and anxiety, stress, and depression.

Gender/hormonal factors

Women are more predisposed to asthma than men. CDC data shows that 9.5% of females are living with asthma compared to 6.1% of men.¹⁰ Symptoms also tend to vary depending on pregnancy, the menstrual cycle, and menopause.

More specifically, higher levels of estrogen and progesterone may increase the symptoms of asthma (called premenstrual asthma). However, this relationship is complex and varies from person to person. 

Experts think that hormonal activity can cause changes in immune system activity, which in turn causes hypersensitivity, inflammation, and aggravated asthma.

Living with mild persistent asthma

There is currently no cure for asthma. Current treatment options aim to manage the disease and keep symptoms under control. Your doctor will recommend an asthma treatment plan depending on your symptoms and triggers. 

Most asthma medicines target three major changes that happen during an asthma attack:

  • Swelling in the airways

  • Mucous production, which can clog the airways

  • Muscles tightening and squeezing the airways

All these symptoms cause breathing problems because they stop air from flowing easily into the lungs. Asthma medication opens the airways and is classified depending on how it works and for how long it keeps the airways open.

Asthma treatments

There are four main types of asthma treatments.

  • Short-acting or quick-relief medicines are used to relieve symptoms quickly. You take them as needed, and they remain active for about 4 hours.

  • Controller medicines correct changes in the airways, such as swelling, mucus, and muscle contraction, but most of these are not quick-acting.

  • Combination quick-relief and controller medication

  • Biologics, which are used for specific types of asthma and are given by injection or infusion

Inhaled corticosteroids (ICS) are artificial corticosteroids that supplement the natural corticosteroids made by the adrenal glands in the kidneys. ICS medications are usually inhaled to target the airways specifically and can be taken daily or as needed. 

For those with severe asthma or who do not respond to conventional medication, there are oral corticosteroids, which offer long-term asthma control. But they can cause adverse side effects such as weight gain, high blood pressure, mood swings, cataracts, and high blood pressure.

Bronchodilator and beta-agonist medications relax the airways and improve airflow. 

In addition, bronchodilators can be short or long-acting. Short-acting beta-agonists (SABA) medications are quick-relief medications, while short-acting muscarinic antagonists (SAMA) are quick-relief medicines that can be taken with a SABA to offer relief for up to 8 hours.

Long-acting beta-agonists (LABA) are controller medicines that come as combinations of different medicines that can keep the airways open for up to 12 hours. Similarly, long-acting muscarinic (LAMA or anticholinergics) medicines work for up to 24 hours, but they are not quick-acting.

Another type of asthma medication is theophylline.¹¹ It comes as a tablet, capsule, solution, or syrup that you take by mouth. It is also taken daily, but it does not offer quick relief for sudden symptoms.

Managing mild asthma

Asthma medication alone will probably not be enough to bring your asthma under control. You will also have to avoid lifestyle and environmental triggers that cause or worsen your symptoms. There are several ways to do that:

  • Make your home allergen-proof — remove carpets, use dust-resistant bedding, and wash curtains and linens regularly

  • Use an air conditioner instead of opening windows to prevent pollen, grass, dust, and traffic fumes from getting in

  • Protect your face from cold air when breathing by wearing a scarf

  • Regularly vacuum your home with a high-efficiency particulate air filter

  • Remove mold traps such as leaves, firewood, and damp areas inside and outside your home

In addition, keep your weight at a healthy level, exercise regularly, eat healthy food, quit smoking, and get flu vaccines. Keep pets out of your bedroom and bathe them at least once a week. Also, keep an inhaler close by at all times in case of a sudden asthma attack.

When you should see a doctor for mild asthma

Even when you're taking medication, asthma can get worse. If you notice that your current medication is no longer effective or that you're experiencing more severe flare-ups, talk to your doctor as soon as possible. 

You should also go to the emergency room immediately if you're experiencing a severe asthma attack. Signs of such an attack include breathlessness, difficulty talking, confusion, severe wheezing, and straining your chest muscles to breathe.

The lowdown

Asthma is classified as either mild, moderate, or severe. Mild persistent asthma won’t cause daily flare-ups and should be well-controlled with treatment.

It is important to keep even mild asthma under control, as there’s a possibility it could develop in severity.

Shortness of breath, mucus buildup in the airways, tightness in the chest, and wheezing are all typical asthma symptoms. If you are experiencing any of these symptoms, make an appointment with your doctor. They will be able to diagnose you and create a suitable treatment plan.

  1. Mild asthma: an expert review on epidemiology, clinical characteristics and treatment recommendations (2007)

  2. Global strategy for asthma management and prevention (2021 update)

  3. National asthma education and prevention program coordinating committee (NAEPPCC) | NIH: National Heart, Lung, and Blood Institute

  4. Overview of changes to asthma guidelines: Diagnosis and screening (2009)

  5. Asthma risk factors (2015)

  6. Obesity and asthma (2019)

  7. Being overweight or obese and the development of asthma (2018)

  8. Incidence and risk factors for exacerbations of asthma during pregnancy (2013)

  9. Maternal smoking during pregnancy affects adult onset of asthma in offspring: a follow up from birth to age 46 years (2020)

  10. Most recent national asthma data | Centers for Disease Control and Prevention (CDC)

  11. Theophylline (2022)

Other sources:

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