In fact, 90 out of 100 children will experience fluid in their ears at some point before the age of 5 or 6. The most causes of this, in both children and adults are allergies, congestion from a cold or other virus, enlarged sinus tissue, exposure to chemical irritants, previous damage to the auditory tube, a rapid change in ambient air pressure, or oral abnormalities, such as those associated with down syndrome or a cleft palate.
