[Environment and asthma in children: controversies]

Area of Science:

• Environmental Health
• Allergology
• Epidemiology

Context:

• Rising asthma prevalence over two decades suggests environmental or hygiene factor involvement.
• Investigates the complex role of environmental exposures, including house dust mite (HDM) and animal dander, in asthma development and severity.
• Contrasts environmental and hygiene theories regarding asthma etiology.

Purpose:

• To review the controversial role of house dust mite (HDM) exposure in asthma.
• To evaluate the protective or deleterious effects of early-life and current exposure to environmental allergens like HDM and animal dander.
• To emphasize the undeniable impact of passive smoking on asthma.

Summary:

• While early exposure to house dust mites (HDM) and animal dander may have protective effects, particularly in low-atopy risk families, current exposure appears detrimental.
• Exposure to dog dander might be more protective than cat dander.
• The negative impact of passive smoking on asthma prevalence and severity is conclusive, necessitating focused efforts for its elimination.

Impact:

• Findings challenge definitive recommendations for early eviction of HDM and animal dander, especially in high-atopy risk families.
• Highlights the need for continued research into the nuanced effects of environmental exposures on asthma.
• Underscores the critical importance of eliminating passive smoking to mitigate asthma burden.