what causes fluid in the ears?
 Upper respiratory allergies and inflammation and swelling of the adenoids, the tissue at the back of the nose, can cause poor fluid drainage from the middle ear to the external ear and therefore cause a blockage in the Eustachian tube. Eustachian Tube Dysfunction (ETD) is often the most common cause of fluid behind eardrum. Common causes for developing fluid in the ear for both adults and children includes any kind of congestion, from a cold virus, similar infection, or even pregnancy. 