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This information was reviewed and approved by Flavia Cecilia Lega Hoyte, MD (2/6/2023).

People with asthma often have chronically inflamed (swollen) airways. Therefore, the airways are sensitive to things that make asthma worse. These, either individually or together, are the asthma triggers that cause symptoms. Identifying and controlling or treating asthma triggers, which make asthma worse and vary from person to person, is essential for good asthma management. It is helpful to think about your last asthma attack. During the attack, did you experience any of the situations described on this page? If so, discuss this information with your health care provider.

woman using her inhaler while jogging


Substances found in the environment can irritate sensitive airways. Common ones include smoke (such as tobacco smoke, wildfire smoke, and smoke from wood-burning or kerosene stoves and fireplaces), aerosol sprays, strong odors (like perfumes, cologne and gasoline fumes), dust and air pollution. Cigarette smoke is a particularly serious asthma trigger. If you have asthma, do not allow smoking in your home or car and always look for non-smoking sections in public areas.


A variety of allergens can make asthma symptoms worse, but it is important to note that not all people with asthma have allergies. Reliable and valid allergy tests are available, and a board-certified allergist can guide you through this process. Common allergens include animal dander, saliva and urine from feathered or furry animals. Other common allergens are dust mites (a major component of house dust in humid climates), cockroaches, mold, pollen, foods and medications.

If you are allergic to any of these substances, making changes in your environment to control or avoid contact with the allergen is very important. It is also important to know what allergens are in your home and how they can contribute to asthma worsening or to an asthma attack. Ask your health care provider about environmental control and read more about the relationship of allergies to asthma.


Infections can also make asthma worse. Common cold viruses, respiratory infections, sinusitis, COVID-19, and influenza frequently cause an increase of asthma symptoms. As a result, your health care provider will likely recommend an annual flu vaccination and staying up to date with COVID-19 vaccines.


Exercise or physical activity can be an asthma trigger. For some, it may be the only cause of asthma symptoms. However, exercise is important for everyone and should not be avoided. Read more about exercise-induced asthma. With the help of your healthcare provider and appropriate treatment, you should be able to exercise without limitations from your asthma.


There are certain types of weather that may cause problems for some people with asthma in any climate. Some weather situations that may make asthma symptoms worse include extremely hot or cold temperatures, windy conditions, and changes in the humidity or barometric pressure.


Emotions do not cause asthma but can make asthma worse, because strong feelings can lead to changes in breathing patterns. However, it is important to express your emotions, and good asthma management can minimize the effect of stress.

Changes in Breathing Patterns

Sneezing, laughing, stress, holding your breath and sleep disorders may cause changes in breathing patterns, which may make asthma worse. It is not always possible or desirable to avoid these situations. However, good asthma management may minimize these effects.

Gastroesophageal Reflux

For certain people, the muscle between the esophagus and stomach may not work well. This can allow the backflow of stomach acid into the esophagus, airway, throat or mouth. This may cause heartburn, but can sometimes manifest as cough, throat clearing, or worsening asthma control. Other people have a slightly abnormal swallow that predisposes to entry of food particles or acid reflux into their lungs, termed airway aspiration. Asthma symptoms that are worse overnight, associated with eating, or accompanied by heartburn, can indicate co-morbid gastroesophageal reflux and/or aspiration. These conditions need to be addressed in order to achieve optimal asthma control.


Many people with asthma also have chronic sinusitis. Sinusitis is an inflammation of the mucous membranes that line the sinus cavities. This can interfere with normal sinus drainage and cause increased mucus production, which can lead to nasal and sinus congestion and drainage down the back of the throat, known as postnasal drip. Sinusitis can make asthma worse, especially at night. A sinus infection can also significantly worsen your asthma or your child’s asthma. Many sinus infections are caused by viruses, which do not require antibiotics, but others are caused by bacteria and would need treatment with an antibiotic.

Nocturnal Asthma

Worsening of asthma at night is very common. There are many asthma triggers present at night that may contribute to increased symptoms. These include:

  • Exposure to allergens in the bedroom, particularly dust mites in humid areas or pets if they are allowed in the bedroom delayed allergic response, which may occur 3–8 hours after exposure 

  • Airway cooling from a drop in body temperature at night

  • Decreased effect of medications during early morning hours right before another dose is due

  • A natural dip in cortisol levels in the early morning hours 

  • Sleep apnea — the brief, repetitive cessation of breathing during sleep, caused by an upper airway obstruction

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