Final answer:
Otitis externa can be differentiated from uncomplicated otitis media by a normal pneumatic otoscopy, indicating that the tympanic membrane moves normally and is not impeded by fluid in the middle ear.
Step-by-step explanation:
Otitis externa can be differentiated from uncomplicated otitis media by normal pneumatic otoscopy. This physical examination finding implies that the tympanic membrane moves normally when pressure is varied, which would not be the case if fluid were present in the middle ear, as in otitis media. The signs of otitis externa include itching, redness, and discomfort in the external ear canal, potentially progressing to fever, pain, and swelling. In acute otitis media (AOM), there typically is a buildup of pus within the middle ear as a result of infection, which causes moderate to severe bulging of the tympanic membrane and might impede its movement, observable during a pneumatic otoscopy. Therefore, a normal pneumatic otoscopy would differentiate otitis externa from AOM. Additional findings in otitis externa might include erythema and severe peeling of the skin in the external auditory canal, often caused by Pseudomonas aeruginosa.