Bronchial asthma - Symptoms, Causes, Treatment & Prevention

Overview

Bronchial asthma (commonly called asthma) is a chronic inflammatory disease of the airways characterized by recurrent episodes of wheezing, shortness of breath, chest tight‑tightness, and coughing. The inflammation causes the bronchial walls to swell and become hyper‑responsive, leading to reversible airway obstruction.

Asthma can begin at any age, but it most often starts in childhood. According to the World Health Organization (WHO), ~339 million people worldwide currently have asthma, and the prevalence is rising, especially in low‑ and middle‑income countries.

In the United States, the Centers for Disease Control and Prevention (CDC) estimates that about 25 million people (≈8 % of the population) have asthma, including 7 million children. The disease affects all genders and ethnicities but is more severe and less well‑controlled in African‑American and Hispanic populations.¹

Symptoms

Asthma symptoms can vary from mild and occasional to severe and persistent. They often worsen at night or early in the morning.

• Wheezing – high‑pitched whistling sound during exhalation.
• Shortness of breath – feeling unable to get enough air, especially during exertion.
• Chest tightness – a sensation of pressure or constriction in the chest.
• Cough – dry, non‑productive cough that may be worse at night or after exercise.
• Difficulty speaking – in severe attacks, speaking in full sentences becomes hard.
• Rapid breathing (tachypnea) – especially in children.
• Fatigue – due to poor sleep from nighttime symptoms.

Triggers such as pollen, cold air, exercise, or viral infections can precipitate an acute episode, often called an asthma exacerbation.

Causes and Risk Factors

Underlying Pathophysiology

Asthma is not caused by a single factor. It results from a complex interaction of genetic susceptibility and environmental exposures that promote airway inflammation.

• Allergic (atopic) asthma – driven by IgE‑mediated response to allergens (dust mites, pet dander, pollen).
• Non‑allergic asthma – triggered by irritants (smoke, chemical fumes), infections, or exercise.
• Occupational asthma – exposure to specific workplace substances (e.g., isocyanates, flour dust).

Risk Factors

• Family history of asthma, eczema, or allergic rhinitis.
• Personal history of atopic dermatitis or allergic rhinitis.
• Exposure to tobacco smoke (including prenatal exposure).
• Air pollution, especially particulate matter (PM2.5) and ozone.
• Obesity – increases inflammation and reduces lung function.
• Respiratory infections in early childhood, particularly severe viral bronchiolitis.
• Living in a damp or mold‑prone environment.
• Occupational exposures (e.g., cleaning agents, spray paints).

Diagnosis

Clinical Evaluation

Diagnosis starts with a detailed history (symptom pattern, triggers, family history) and a physical exam. While wheezing may be heard, a normal exam does not exclude asthma.

Objective Tests

1. Spirometry – measures forced expiratory volume in 1 second (FEV₁) and forced vital capacity (FVC). A >12 % increase in FEV₁ after a bronchodilator confirms reversible airway obstruction.
2. Peak Expiratory Flow (PEF) Monitoring – patient‑performed device recorded over weeks; variability >10 % supports diagnosis.
3. Bronchoprovocation Testing – methacholine or exercise challenge to assess airway hyper‑responsiveness when baseline spirometry is normal.
4. Fractional exhaled nitric oxide (FeNO) – elevated levels indicate eosinophilic airway inflammation and help guide inhaled steroid therapy.
5. Allergy testing – skin prick or specific IgE blood tests to identify sensitizing allergens.

Guidelines from the Global Initiative for Asthma (GINA) and the National Heart, Lung, and Blood Institute (NHLBI) recommend confirming diagnosis with at least one objective measurement of airway limitation.

Treatment Options

Treatment goals are to achieve symptom control, prevent exacerbations, and maintain normal activity levels while minimizing medication side effects.

Stepwise Pharmacologic Therapy (GINA 2025)

1. Reliever (quick‑acting) medication – short‑acting β₂‑agonists (SABAs) such as albuterol. Used at the onset of symptoms.
2. Controller (maintenance) medication – taken daily to reduce underlying inflammation.
   • Inhaled corticosteroids (ICS) – budesonide, fluticasone. First‑line for persistent asthma.
   • Low‑dose combination inhalers (ICS/LABA) – e.g., fluticasone/salmeterol for moderate disease.
   • Leukotriene receptor antagonists (LTRAs) – montelukast, especially useful in allergic asthma or when adherence to inhalers is problematic.
   • Biologic agents for severe eosinophilic asthma – omalizumab (anti‑IgE), mepolizumab, benralizumab, dupilumab (anti‑IL‑4/13).
3. Add‑on treatments for uncontrolled disease – tiotropium (long‑acting anticholinergic), oral corticosteroids (short bursts for exacerbations).

Non‑pharmacologic Measures

• Trigger avoidance – use allergen‑impermeable bedding, keep indoor humidity < 50 %, avoid tobacco smoke.
• Asthma action plan – written, personalized plan outlining daily meds, how to recognize worsening, and when to use relievers.
• Vaccinations – annual influenza vaccine and pneumococcal vaccination reduce infection‑related exacerbations.
• Pulmonary rehabilitation – breathing exercises (e.g., diaphragmatic breathing) improve control.

Living with Bronchial Asthma

Daily Management Tips

• Carry a reliever inhaler at all times.
• Use a spacer with metered‑dose inhalers to improve drug delivery.
• Monitor peak flow daily; note patterns that may precede attacks.
• Maintain an up‑to‑date asthma action plan and review it with your clinician at least twice a year.
• Keep an asthma diary (symptoms, triggers, medication use) to identify patterns.
• Stay physically active; pre‑exercise inhalation of a reliever can prevent exercise‑induced bronchoconstriction.
• Manage comorbidities (e.g., allergic rhinitis, GERD, obesity) as they can worsen asthma control.
• Educate family, school personnel, or coworkers about your triggers and emergency plan.

Special Situations

• Pregnancy – most asthma meds are safe; uncontrolled asthma poses greater risk to mother and fetus.
• Travel – bring extra inhalers, a copy of prescriptions, and a letter from your physician for airline security.
• Children – use age‑appropriate inhaler devices (e.g., press‑urized metered‑dose inhaler with spacer or dry‑powder inhaler) and involve caregivers in monitoring.

Prevention

While you cannot “prevent” a genetic predisposition to asthma, you can reduce the likelihood of developing symptoms or severe disease.

• Stop smoking and avoid second‑hand smoke.
• Breastfeed infants for at least 4–6 months; studies show a modest protective effect.
• Control indoor allergens – encase mattresses, wash bedding weekly in hot water, use HEPA filters.
• Limit exposure to air pollutants – stay indoors on high‑ozone days, use masks when exposure unavoidable.
• Maintain a healthy weight and encourage regular aerobic activity.
• Ensure timely treatment of respiratory infections with antivirals when appropriate.
• Consider early allergen immunotherapy for children with severe allergic rhinitis who are at high risk for asthma.

Complications

If asthma is poorly controlled, the following complications may arise:

• Frequent exacerbations leading to emergency department visits or hospitalizations.
• Permanent airway remodeling – thickening of the bronchial wall, reduced lung function.
• Reduced quality of life, missed school or work days, and psychosocial stress.
• Rarely, status asthmaticus – a life‑threatening, prolonged asthma attack that does not respond to standard therapy.
• Complications from long‑term oral corticosteroid use (osteoporosis, diabetes, hypertension).

When to Seek Emergency Care

References

1. Centers for Disease Control and Prevention. Asthma Data, Statistics, and Surveillance. Updated 2023.
2. World Health Organization. Asthma Fact Sheet. 2022.
3. Global Initiative for Asthma (GINA). 2025 GINA Report.
4. Mayo Clinic. Asthma – Symptoms and Causes. Accessed April 2026.
5. Cleveland Clinic. Asthma Overview. 2024.
6. National Heart, Lung, and Blood Institute. Asthma. Updated 2023.