This patient has otitis media with effusion (OME), and clinical observation is the most appropriate next step in management. OME is defined as fluid in the middle ear but without signs of infection. It is associated with eustachian tube dysfunction, which impairs drainage and causes retention of fluid in the middle ear, and frequently occurs following an upper respiratory tract infection or with exacerbation of seasonal allergies, as in this patient. Patients with OME frequently present with symptoms of aural fullness and hearing loss, and examination shows clear or yellowish fluid present behind a retracted tympanic membrane. Most cases of OME will resolve without treatment over the course of 12 weeks. Although many patients with OME are treated with decongestants, antihistamines, or nasal glucocorticoids, evidence of effectiveness is very limited. However, treatments focused on symptoms associated with underlying conditions that may be contributing to eustachian tube dysfunction and OME, such as the nasal congestion with seasonal allergies in this patient, would be reasonable.

Acute otitis media is characterized by fluid and inflammation in the middle ear accompanied by symptoms of infection. Although evidence to guide treatment of acute otitis media in adults is lacking, oral antibiotics such as amoxicillin, along with analgesics and decongestants, are the mainstays of therapy. This patient has no evidence of infection, and antibiotic therapy is therefore not indicated.

Otitis externa is inflammation of the external ear canal and may present either acutely or chronically. Examination shows inflammation of the external ear canal, and treatment may be with a combined antibiotic and glucocorticoid–containing ototopical agent such as combination neomycin, polymyxin B, and hydrocortisone. In this patient with no evidence of external ear canal inflammation on examination, neomycin, polymyxin B, and hydrocortisone ear drops are not indicated.

Although symptoms of OME will resolve in most patients within 12 weeks, those with persistent symptoms beyond that time period who have not responded to other interventions may be considered for myringotomy with tympanostomy tubes. It would be premature to pursue this treatment at this point in this patient's course.