Dry rales and wet rales are both respiratory additive sounds, which are abnormal sounds that accompany a person’s breath sounds. Wet rales, also known as hyperhydrosis, are sounds produced by the airflow through the airway where there is fluid, causing bubbles to burst, hence the name blistering sound, and are commonly associated with inflammatory changes in the lungs leading to inflammatory exudation. Dry rales, on the other hand, are abnormal sounds caused by vibrations or eddy currents of airflow through a narrow area, and are commonly associated with bronchospasm or partial bronchial obstruction. Croup is a type of dry rales with a higher pitch, but rhythmic dry rales, with the expiratory phase being greater than the inspiratory phase and appearing more often during exhalation, most often in cases of bronchial asthma and acute exacerbation of chronic obstructive pulmonary disease.