Medical Terminology for Allergy-Induced Asthma
The medical term for allergy-induced asthma is "allergic asthma" or "extrinsic asthma." 1, 2
Definition and Characteristics
Allergic asthma is defined as asthma associated with sensitization to aeroallergens, which leads to asthma symptoms and airway inflammation. 1 This is the most common asthma phenotype, accounting for approximately 50% of all asthmatic patients who demonstrate an inborn tendency to atopy. 3
Key Diagnostic Features
The diagnosis is established through:
- Clinical correlation between allergen exposure and symptoms - patients experience symptoms at the same time and place of allergen exposure 3
- Positive skin prick tests or specific IgE antibodies to aeroallergens - demonstrating sensitization to environmental allergens 1, 2
- History of atopic comorbidities - frequently accompanied by allergic rhinitis, atopic dermatitis, and allergic conjunctivitis 4, 2
Alternative Terminology
The term "extrinsic asthma" is used interchangeably with allergic asthma in medical literature, distinguishing it from "intrinsic asthma" (non-allergic asthma). 3, 5 This terminology emphasizes that the asthma is triggered by external allergens rather than non-allergic factors.
Related Specific Terms
- "Type 2 asthma" - a broader category characterized by type 2 airway inflammation with high blood eosinophils and/or elevated FeNO, which includes but is not limited to allergic asthma 4
- "Eosinophilic asthma" - often overlaps with allergic asthma but specifically refers to adult-onset asthma with high blood eosinophils (≥150 cells/μL) 4
Clinical Distinctions
Allergic asthma typically begins at an earlier age than intrinsic asthma, is generally less severe, and seldom evolves toward chronic ventilatory impairment. 3 The condition is driven by a TH2-mediated immune response, with biomarkers including elevated serum IgE levels, positive allergen-specific IgE or skin tests, blood and sputum eosinophilia, and elevated fraction of exhaled nitric oxide (FeNO). 1
Common Allergen Triggers
The most frequently implicated allergens include:
- House dust mites 4, 6
- Animal dander (furs or feathers of domesticated animals) 4, 6, 3
- Pollens 4, 6, 3
- Fungal allergens 4, 6
Pathophysiology
When IgE on mast cells is cross-linked by an allergen, it causes degranulation and release of histamine, neutral proteases, and chemotactic factors, along with production of cysteinyl leukotrienes and prostaglandin D2. 7 This mechanism underlies both the early asthmatic response (within 30 minutes) and late asthmatic response (3-12 hours after exposure). 7