Why colds, flu, RSV and COVID-19 can trigger symptoms – and how to respond
Patient education from Laura Ispas, MD
Founder and Medical Director, Allergy Asthma & Immunology Institute
THE SHORT ANSWER
Respiratory infections – especially viral infections – are common triggers for asthma flare-ups. They can increase airway inflammation, mucus and airway sensitivity. A written asthma action plan and consistent use of prescribed inhaled corticosteroid-containing treatment can reduce the risk of a severe flare.
What happens in the lungs?
Asthma is a chronic condition in which the airways are inflamed and can narrow in response to triggers. During a respiratory infection, the immune response may add more inflammation and mucus. The muscles around the airways may tighten, making it harder to move air in and out.
Symptoms may include:
- More coughing, especially at night or early in the morning
- Wheezing or a whistling sound with breathing
- Chest tightness, shortness of breath or reduced exercise tolerance
- Needing a prescribed reliever inhaler more often than usual
- Lower peak-flow readings, if peak-flow monitoring is part of your plan
Which infections commonly trigger asthma?
Viral upper-respiratory infections are among the most frequent causes of asthma exacerbations. Common examples include rhinovirus (the usual cause of a cold), influenza, respiratory syncytial virus (RSV) and SARS-CoV-2, the virus that causes COVID-19.
Bacterial infections can occur, but they are a less common cause of a typical asthma flare. Yellow or green mucus alone does not prove a bacterial infection. Antibiotics do not treat viruses or asthma inflammation and should be used only when a clinician identifies or strongly suspects a bacterial infection.
Does asthma make infections more likely?
Asthma does not automatically mean that a person catches every infection more easily. However, respiratory infections can cause more serious breathing problems in people with asthma, particularly when asthma is poorly controlled. Some patients also have a separate immune deficiency or another condition that increases infection risk. Recurrent, unusually severe or persistent infections deserve individualized evaluation.
What to do when illness begins
Follow your written asthma action plan. If you do not have one, ask your clinician to prepare one with you. The plan should explain which daily medicines to continue, which reliever to use, when to contact the office and when to seek emergency care.
- Continue prescribed asthma controller treatment, including inhaled corticosteroid-containing medication, unless your clinician tells you otherwise.
- Use your prescribed reliever exactly as directed in your action plan. If it is not lasting or is needed more often than directed, seek medical advice promptly.
- Rest, drink fluids as appropriate for you, and avoid smoke, vaping, strong odors and other known triggers.
- Check symptoms and peak flow, if prescribed. Pay attention to nighttime waking and difficulty speaking, walking or doing usual activities.
- Contact your clinician early if symptoms are worsening, especially if you have had severe attacks, emergency visits or hospitalization in the past.
IMPORTANT
Do not start leftover antibiotics, oral steroids or someone else’s medication. Some patients need a short course of oral corticosteroids during a significant exacerbation, but this decision should follow the patient’s written plan or prompt clinical assessment.
When to get urgent or emergency help
Call 911 or go to the nearest emergency department for severe breathing difficulty, blue or gray lips, confusion or marked drowsiness, inability to speak in full sentences, fainting or near-fainting, or little/no improvement after using the prescribed reliever. Do not drive yourself if you are severely short of breath.
Seek same-day medical advice if symptoms are worsening, the reliever is needed more often than your plan allows, nighttime symptoms are increasing, peak flow has dropped into the yellow or red zone, or fever and respiratory symptoms are persistent or concerning.
Reducing the risk of infection-related flares
- Keep asthma well controlled. Regular treatment with an inhaled corticosteroid-containing medication substantially reduces the risk of severe exacerbations.
- Review inhaler and spacer technique. Even an excellent prescription will not work well if the medicine does not reach the lungs.
- Stay current with recommended vaccines, including influenza and COVID-19. Ask your clinician which pneumococcal and RSV vaccines are appropriate for your age, health conditions and vaccination history.
- Wash hands, improve ventilation in crowded indoor spaces, and consider a well-fitting mask when exposure risk is high.
- Avoid tobacco smoke and vaping. Identify and reduce other triggers such as allergens, pollution or occupational exposures.
- Schedule periodic asthma reviews, even when you feel well, and update your written action plan.
Personalized asthma care in Leesburg, Virginia
At Allergy Asthma & Immunology Institute, Laura Ispas, MD, evaluates children age 5 and older and adults with asthma, allergies and immune-related conditions. Dr. Ispas has more than 25 years of clinical experience and develops individualized plans based on symptoms, lung function, triggers, treatment response and the patient’s medical history.
Depending on the patient’s needs, an evaluation may include:
- Asthma assessment and pulmonary function testing
- Review of inhaler technique and a personalized asthma action plan
- Allergy testing and environmental-trigger counseling
- Controller and reliever medication review
- Biologic therapy assessment for eligible patients with difficult-to-control asthma
- Immune evaluation when infections are recurrent, severe or unusual
REQUEST AN APPOINTMENT
Call or text 571-399-5132. Allergy Asthma & Immunology Institute is located at 19455 Deerfield Avenue, Suite 207, Leesburg, VA 20176 – directly across from Inova Loudoun Hospital, with convenient access from Route 7.
Frequently asked questions
Can a common cold trigger an asthma attack?
Yes. Viral respiratory infections are a common trigger for asthma exacerbations. Follow your action plan and contact your clinician if symptoms are worsening or your prescribed reliever is not providing adequate relief.
Should I stop my controller inhaler when I am sick?
Usually no. Continue prescribed asthma medicines, particularly inhaled corticosteroid-containing treatment, unless your clinician directs otherwise. Your written plan may contain specific temporary adjustments.
Do I need an antibiotic for green mucus?
Not necessarily. Mucus color alone cannot determine whether an infection is bacterial. Antibiotics do not treat viral infections or asthma inflammation. A clinician should decide whether an antibiotic is appropriate.
How long can asthma symptoms last after an infection?
Cough and airway sensitivity can continue after the initial infection improves. Persistent, worsening or recurrent symptoms should be assessed, especially if sleep, activity or breathing is affected.
Can allergy treatment improve infection-triggered asthma?
For patients whose asthma is also triggered by allergens, identifying and treating allergic disease may improve overall asthma control. Treatment must be individualized; allergy immunotherapy and biologic therapy are appropriate only for selected patients.
Sources and medical review
Clinical framework: Global Initiative for Asthma (GINA), 2026 Summary Guide
Patient prevention guidance: CDC – Respiratory Infections and Asthma
Vaccination guidance: CDC – Pneumococcal Vaccine Recommendations
Medical content reviewed and updated for patient education by Laura Ispas, MD, Allergy & Immunology Specialist. Updated August 2026
This handout provides general education and does not replace an individualized diagnosis, treatment plan or emergency care. Vaccine and medication recommendations vary by age, medical history and prior treatment.
