The positive rate of dermal sensitivity test in 88 urban patients readed as follows Asthma was 70.8 percent,chronic trac城市88 例患者的皮试阳性率哮喘为708 ％ 、慢性气管炎77 ％ 、荨麻疹7 ％ 、过敏紫癜9 ％ 。