What is the "hygiene hypothesis" in asthma?
Keeping children's hands clean will reduce asthma rates
Exposing children to pathogens at a young age will decrease their risk for asthma
Dirty water is responsible for many cases of asthma in the developing world
Frequent bathing can reduce the severity of asthma attacks
All of the following changes may be seen in chronic asthma except .
hypertrophy and hyperplasia of mucus glands
destruction of alveolar septa and pulmonary capillaries
epithelial desquamation
deposition of subepithelial collagen
