Effective allergen avoidance at high altitude reduces allergen-induced bronchial hyperresponsiveness

Area of Science:

• Allergy and Immunology
• Pediatric Pulmonology
• Environmental Health

Background:

• Asthma in children is often exacerbated by house dust mite (HDM) allergies.
• Reduced allergen exposure is a key management strategy for allergic asthma.
• High-altitude environments can offer reduced allergen exposure.

Purpose of the Study:

• To investigate the impact of reduced allergen exposure at high altitude on bronchial hyperreactivity (BHR) in children with HDM-allergic asthma.
• To assess changes in allergen-specific IgE levels and bronchial provocation test responses.

Main Methods:

• Two groups of asthmatic children allergic to HDM lived at high altitude for 9 months.
• Serum IgE levels, peak expiratory flow (PEF) after exercise, and methacholine and histamine challenges were measured.
• Bronchial hyperreactivity (BHR) was assessed using methacholine and histamine provocation tests.

Main Results:

• Significant decreases in total and HDM-specific IgE were observed after 3 and 9 months.
• Improvement in PEF fall after exercise and increased methacholine PD20-FEV1 were noted.
• HDM PD20-FEV1 and histamine PD20-FEV1 increased, indicating reduced bronchial hyperreactivity and allergen sensitivity.
• Reversal of improvements occurred upon return to sea level.

Conclusions:

• Reduced allergen exposure at high altitude effectively decreases nonspecific BHR in asthmatic children.
• Allergen avoidance also reduces allergen sensitivity and late allergen-induced bronchial reactions.
• These findings underscore the therapeutic benefit of allergen avoidance for managing pediatric asthma.