Allergic Asthma

Introduction

Allergic asthma is a chronic inflammatory airway disease triggered by exposure to allergens such as dust mites, pollen, mold, or animal dander. It is characterized by reversible airway obstruction, bronchial hyperresponsiveness, and symptoms such as wheezing, coughing, chest tightness, and shortness of breath. The underlying pathophysiology involves IgE-mediated hypersensitivity and chronic airway inflammation. Treatment aims to control symptoms, prevent exacerbations, and improve quality of life through a stepwise approach guided by disease severity.

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Treatment Options and Doses

1. Short-Acting Beta₂-Agonists (SABA) – Rescue Therapy

• Salbutamol (Albuterol): 90–180 mcg inhaled every 4–6 hours as needed.

• Levalbuterol: 45 mcg inhaled every 4–6 hours as needed.
  Used for immediate relief of acute bronchospasm.

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2. Inhaled Corticosteroids (ICS) – First-Line Controller Therapy

• Budesonide: 180–600 mcg/day in divided doses (adults).

• Fluticasone propionate: 100–500 mcg twice daily via inhalation.

• Beclomethasone: 40–320 mcg twice daily.
   Reduces airway inflammation and prevents exacerbations.

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3. Leukotriene Receptor Antagonists (LTRA)

• Montelukast:

  • Adults: 10 mg orally once daily in the evening.

  • Children (6–14 years): 5 mg once daily.

• Zafirlukast: 20 mg orally twice daily (adults).
   Useful as add-on therapy, especially in patients with allergic triggers.

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4. Long-Acting Beta₂-Agonists (LABA) – Always Combined with ICS

• Salmeterol: 50 mcg inhaled twice daily.

• Formoterol: 12 mcg inhaled twice daily.
   Improves symptom control; not used as monotherapy.

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5. Combination Therapy (ICS + LABA)

• Fluticasone + Salmeterol (e.g., Advair): 100/50 mcg to 500/50 mcg inhaled twice daily.

• Budesonide + Formoterol (e.g., Symbicort): 160/4.5 mcg, 2 inhalations twice daily.
   Preferred for moderate to severe persistent asthma.

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6. Anti-IgE Therapy (Biologic Therapy for Severe Allergic Asthma)

• Omalizumab: Subcutaneous injection every 2–4 weeks.

  • Dose: 150–375 mg, based on body weight and baseline serum IgE levels.
     Indicated for patients with severe allergic asthma uncontrolled by ICS/LABA.

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7. Oral Corticosteroids (Systemic – for Severe or Acute Exacerbations)

• Prednisone: 40–60 mg orally once daily for 5–10 days (adults).

• Methylprednisolone: 40–125 mg IV every 6–8 hours (hospitalized severe cases).
   Used short-term due to risk of significant side effects.

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Key Considerations

• Stepwise approach: Therapy is escalated or de-escalated based on control.

• Allergen avoidance and environmental control are essential adjuncts.

• Immunotherapy (allergen-specific) may benefit selected patients.

• Biologics (e.g., omalizumab, dupilumab, mepolizumab) are reserved for severe, uncontrolled cases.

• Monitoring: Peak flow measurements and symptom diaries guide treatment adjustments.