Table 4.

Categories of Asthma According to Etiology, Clinical Patterns, and Underlying Mechanisms

Related triggers (environment)	Inflammatory patterns	Clinical courses	Mechanisms
Aspirin or NSAID	Eosinophilic	Severity-defined	Th2 dominant
Environmental allergens	Neutrophilic	Exacerbation-prone	Th1 dominant
Occupational irritants	Pauci-granulocytic	Chronic airflow restriction	Th17 dominant
Hormonal changes		Resistance to steroids	Innate Th2 dominant
Exercise		Age at onset	Epithelial dysfunction
Viral infection
Obesity

NSAID, nonsteroidal anti-inflammatory drugs.