The common cause of all forms of<unk>  is dysfunction of the Eustachian tube. This is usually due to inflammation of the mucous membranes in the nasopharynx, which can be caused by a viral upper respiratory tract infection (URTI), strep throat, or possibly by allergies. By reflux or aspiration of unwanted secretions from the nasopharynx into the normally sterile middle-ear space, the fluid may then become infected — usually with bacteria. The virus that caused the initial upper respiratory infection can itself be identified as the pathogen causing the infection.
Otitis media
Chorditis
Rhinitis medicamentosa
Aerosinusitis
Fungal sinusitis
Otitis externa
Rhinosinusitis
Streptococcal pharyngitis