Bullae are rounded or irregularly shaped blisters containing serous or seropurulent fluid.They differ from vesicles only in size, being larger than 1 cm. 大疱为圆形或不规则形的大水疱，含浆液性浆液脓性液体，大于1cm，与水疱仅是大小之别。
or the broken bleb may leave a raw and moist base, which may be covered with seropurulent or purulent exudates. 或者，大疱破后留下粗糙、湿润的基底面，其上覆盖浆液脓性或脓性分泌物。
