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Asthma: Triggers, Pathophysiology, and Management Essentials

Understanding Asthma

Asthma is a chronic inflammatory airway disease characterized by variable expiratory airflow limitation and airway hyperresponsiveness. Affecting ~25 million Americans (8%), its pathophysiology involves Th2 inflammation (eosinophilic) → edema, mucus hypersecretion, smooth muscle hypertrophy → bronchoconstriction.

Common Triggers (Highly Individualized)

  • Allergens: Dust mites, pet dander, mold, pollen, cockroach, rodents
  • Irritants: Tobacco smoke (including second/third-hand), vaping, air pollution, strong odors, cleaning chemicals, cold air
  • Respiratory infections: Rhinovirus, RSV, influenza, COVID-19
  • Exercise: Exercise-induced bronchoconstriction (EIB)—especially in cold/dry air
  • Weather changes: Temperature/humidity shifts, thunderstorms
  • Emotions/stress: Laughter, crying, anxiety
  • Medications: Aspirin/NSAIDs (AERD: aspirin-exacerbated respiratory disease), beta-blockers (non-selective)
  • GERD: Microaspiration/vagal reflex
  • Hormonal: Premenstrual, pregnancy

Diagnosis

  • History: Recurrent wheeze, cough, dyspnea, chest tightness—variable, trigger-linked
  • Spirometry: FEV1/FVC < LLN; ≥12% & 200 mL FEV1 reversibility post-bronchodilator
  • Bronchoprovocation (methacholine, mannitol, exercise) if spirometry normal
  • FeNO (fractional exhaled NO): >25 ppb supports eosinophilic inflammation
  • Allergy testing (skin prick/sIgE) for allergic phenotype

Management (GINA/NAEPP Guidelines)

Controller (Maintenance) Therapy

  • Step 1 (mild intermittent): Low-dose ICS-formoterol PRN (preferred) OR SABA PRN + consider low-dose ICS
  • Step 2 (mild persistent): Daily low-dose ICS + SABA PRN OR low-dose ICS-formoterol maintenance+reliever (MART)
  • Step 3 (moderate): Low-dose ICS-LABA maintenance + SABA PRN OR MART
  • Step 4 (severe): Medium/high-dose ICS-LABA + consider LAMA, LTRA, theophylline
  • Step 5 (severe uncontrolled): Refer for biologics (anti-IgE, anti-IL5/5R, anti-IL4Rα, anti-TSLP) ± high-dose ICS-LABA

Reliever Therapy

  • ICS-formoterol PRN (preferred—reduces severe exacerbations vs SABA alone)
  • SABA (albuterol) if not on MART

Non-Pharmacologic

  • Trigger avoidance + environmental control (dust mite covers, HEPA, no smoking)
  • Written asthma action plan (green/yellow/red zones)
  • Vaccinations: Flu, COVID, pneumococcal, RSV (older adults)
  • Comorbidity management: Allergic rhinitis, GERD, obesity, OSA, anxiety/depression
  • Smoking cessation—critical

Red Flags for Urgent Care

  • Speaking in phrases, accessory muscle use, SpO2 <92%, PEF <50% personal best, altered mental status, no relief from SABA

Asthma is controllable. Partnership with a provider, adherence to controller therapy, and a personalized action plan enable full, active lives.

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