In accordance with the motto of this year’s World Asthma Day, “Uncovering Asthma Misconceptions”, this is the third post of our mini-series about asthma based on our patient booklet “Fast Facts for Patients and their Supporters: Asthma”. Here, we focus on the triggers, risk factors, types and severity of asthma.

Risk Factors

Asthma can develop at any age. The causes of asthma vary from person to person, and there are a number of risk factors (such as your genes, level of immunity, physical development and interactions with the environment) that increase the likelihood of asthma developing. They are different from the ‘triggers’ that bring on an asthma attack or cause asthma to worsen.


Risk factors of asthma



Triggers do not cause asthma to develop, but they can make the symptoms of asthma worse or cause an asthma attack. Triggers are any substance or physical irritant that bring on asthma symptoms. Some bring on symptoms rapidly, but once the trigger is removed the symptoms tend to resolve.

Once you know what your triggers are you can try to reduce your contact with them (although some triggers are hard to avoid). This will reduce your risk of attacks and help you to manage your asthma better.


Triggers of asthma



Allergens can be a risk factor for asthma as well as a trigger. As triggers, they often cause serious symptoms. If you think you may be allergic to something, talk to your doctor about allergy skin testing.

AllergenWhat you can do
• Common in areas where moisture builds up• Keep surfaces dry
• Check for mold behind appliances
• Check for mold before buying a new home
Animal dander
• Small particles of skin in animal fur that contain proteins (the true allergen)
• Animal saliva and urine can also contain these proteins
• Allergy to cat fur is common; allergies to dogs, rodents and birds also cause asthma symptoms
• Allergies to horse and rabbit hair can cause life-threatening attacks
• Try to avoid animals that make your symptoms worse
• If you have a pet that affects you, keep the animal outside and sleeping area regularly wash your pet’s fur and sleeping area
House dust mites
• Present in nearly all homes
• Most commonly found in bedclothes, mattresses and carpets
• Numbers increase in humid warm conditions (over 55% humidity, over 15°C)
• Vacuum daily
• Wash bedclothes frequently (in a hot wash over 55°C)
• Avoid man-made materials
• Replace carpets with hard flooring
• Common food allergies include nuts (especially peanuts), shellfish, eggs and berries
• Allergy to these foods can cause anaphylaxis (a sudden and serious allergic reaction), which can be fatal
• Check food labels and ask about ingredients in restaurants
• Be aware that peanut oil is commonly added to some foods
• If you have a serious food allergy, always keep an epinephrine (adrenaline) auto-injector with you and make sure you, and the people around you, know how to use it
• Grasses, trees, flowering plants and weeds all release pollens
• Symptoms are often seasonal depending on when and how often different types of pollen are released
• Thunderstorms can break pollen into smaller pieces that go deeper into the small airways
• Be aware of pollen count forecasts; take allergy medications before symptoms start
• Plan outdoor activities for low-pollen times
• Stay indoors and keep windows shut on windy days and during thunderstorms
• Can cause both anaphylaxis and asthma symptoms on contact• Avoid contact with, for example, latex gloves, condoms or balloons

Different Types of Asthma

  • Childhood asthma is the most common type of asthma. It is often caused by allergies or exposure to viruses. Symptoms resolve in over two-thirds of children as they grow older.
  • Adolescent- and adult-onset asthma can develop after a severe viral illness or from an allergy.
  • Occupational asthma is triggered by certain exposures in the workplace (for example, dust or chemicals).
  • Seasonal asthma improves or worsens as the seasons change. Examples of triggers are cold weather and different types of pollen.
  • Exercise-induced asthma occurs during and after exercise.
  • Catamenial (or perimenstrual) asthma worsens around the time of a woman’s period.

Severity of Asthma

Your doctor will grade your asthma as mild, moderate or severe, depending on how bad your symptoms are and the level of treatment you require. Asthma with a lot of symptoms and/or very serious attacks or worsening symptoms is often described as difficult to control or severe.


Please check out the previous and the next post of our series here:

Please also check out the knowledge transfer “Let’s Talk about Asthma and Fungal Spores” published on this blog.


Information based on Fast Facts for Patients and their Supporters: Asthma (Karger, 2020).

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