Which condition is characterized by the presence of excess fluid behind the eardrum?

The presence of excess fluid behind the eardrum is most closely associated with serous otitis media. This condition, often seen in children but can occur in adults, occurs when fluid accumulates in the middle ear space without signs of acute infection. It typically follows Eustachian tube dysfunction, which can cause the tube to remain blocked, leading to fluid retention. The fluid buildup can be due to a variety of factors, including allergies, upper respiratory infections, or atmospheric pressure changes, but it does not involve the acute inflammation or infection that characterizes other types of otitis media. Therefore, serous otitis media is specifically identified by the non-infectious accumulation of fluid in the middle ear, distinguishing it from conditions such as acute otitis media, which involves bacterial or viral infection and presents with more pronounced symptoms such as pain, fever, and redness of the eardrum.