Otalgia is defined as ear pain. Two separate and distinct types of otalgia exist. Pain that originates within the ear is primary otalgia; pain that originates outside the ear is referred otalgia.
Typical sources of primary otalgia are external otitis, otitis media, mastoiditis, andauricular infections. Most physicians are well trained in the diagnosis of these conditions. When an ear is draining and accompanied by tympanic membrane perforation, simply looking in the ear and noting the pathology can make the diagnosis. When the tympanic membrane appears normal, however, the diagnosis becomes more difficult.
Referred otalgia is a topic unto itself. Although many entities can cause referred otalgia, their relationship to ear pain must be identified. A categorical discussion of the workup, treatment, prognosis, demographics, and other issues is impossible because the various pathologies responsible for creating referred otalgia are so diverse.
Reports document that not all otalgia originates from the ear. Many remote anatomic sites share dual innervation with the ear, and noxious stimuli to these areas may be perceived as otogenic pain. By definition, referred otalgia is the sensation of ear pain originating from a source outside the ear.
To better understand referred otalgia, the physician first must understand the anatomic distribution of nerves associated with the ear. Irritation of these nerves, as well as irritation of distant branches of these nerves, can cause the perception of pain within the ear.
The picture below demonstrates the diversity of pathologies that can be the source of referred otalgia.