Table 1.

Differences between asthma and COPD.

	Asthma	COPD
Age at onset	At any age (usually <40 years)	Usually >40 years
Smoking history	Possible	Usually >10 pack-years
Cough at exacerbation	Usually between 2 and 6 am	Gradual increase
Sputum production	Infrequent	Common
Allergy (eczema or allergic rhinitis)	Common	Infrequent
Airway inflammation
Main portion	Large airways	Small airways
Pathophysiology	Basement-membrane thickening	Fibrosis of small airways
	Increased airway smooth muscle	Destruction of alveolar walls
Bronchial biopsies	Th2-dominant T cells	Th1-dominant T cells and type1 CTL
	Eosinophils, activated mast cells	Neutrophils and Mφ
Reversibility (peak flow results)	Normalize with time	May improve, but do not normalize
Family history	Common	Uncommon

CTL, cytotoxic T cell; Mφ , macrophage.