How can otitis externa be differentiated from uncomplicated otitis media during a physical examination?

Differentiating otitis externa from uncomplicated otitis media can often be accomplished through careful observation during a physical examination. When performing pneumatic otoscopy, one would notice that in a case of uncomplicated otitis media, there may be signs of fluid accumulation behind the tympanic membrane, which typically results in a dull appearance and decreased mobility. In contrast, during otitis externa, the tympanic membrane might appear normal upon pneumatic otoscopy because the condition primarily affects the outer ear canal, rather than the middle ear. Therefore, a normal pneumatic otoscopy is a key finding that helps indicate the absence of middle ear involvement, effectively distinguishing otitis externa from otitis media.

Other findings, such as an erythematous tympanic membrane, mastoid tenderness, and posterior auricular adenopathy, may suggest possible complications or different diagnoses associated with inner ear conditions but do not specifically serve to differentiate between otitis externa and uncomplicated otitis media. Hence, the normal findings noted during pneumatic otoscopy provide a clear distinction essential for accurate diagnosis and treatment.