Cough variant asthma and atopic cough

Table 2 Cough caused by eosinophilic airway diseases

	Asthma	Cough variant asthma	Atopic cough	Eosinophilic bronchitis
Symptoms	Cough, breathlessness, wheeze	Cough only	Cough only	Cough and sputum
Atopy	Common	Common	Common	As in general population
Variable airflow obstruction	+	±	-	-
Airway hyper-responsiveness	+	+	-	-
Capsaicin cough hyper-responsiveness	±	±	-	+
Bronchodilator response	+	+	-	-
Corticosteroid response	+	+	+	+
Response to H₁ antagonist	±	±	+	NK
Progression to asthma	n/a	30%	rare	10%
Sputum eosinophilia (> 3%)	Frequent	Frequent	Frequent	Always (by definition)
Submucosal eosinophils	↑	↑	↑	↑
BAL eosinophilia	↑	↑	↓	↑
Mast cells in ASM	↑	↓	NK	↓
Basement membrane thickness	↑	↑	NK	↑

Definition of abbreviations: ASM, airway smooth muscle; BAL, bronchoalveolar lavage; n/a, not applicable; NK, not known.
+ = often present.
± = sometimes present.
- = not present.
↑ = increased.
↓ = not increased.

ISSN: 2049-6958