Differential Diagnosis for Left Ear Discomfort and Associated Symptoms

Single Most Likely Diagnosis

• Eustachian Tube Dysfunction (ETD): This condition is characterized by the inability of the Eustachian tube to open and close properly, leading to a sensation of fullness or blockage in the ear, which could explain the feeling of being underwater when people talk. The nasal congestion and difficulty breathing through one nostril can also contribute to ETD, as the Eustachian tube connects the middle ear to the back of the nose and throat. Tinnitus can be a symptom of ETD due to the abnormal pressure in the middle ear.

Other Likely Diagnoses

• Middle Ear Effusion: Fluid accumulation in the middle ear can cause a feeling of fullness, hearing difficulties, and tinnitus. The "crinkly paper" sound described could be due to the movement of fluid in the ear.
• Sinusitis: Given the nasal congestion and difficulty breathing through one nostril, sinusitis, especially if it involves the sinuses that drain near the Eustachian tube, could contribute to the ear symptoms by causing Eustachian tube dysfunction.
• Allergic Rhinitis: Similar to sinusitis, allergic rhinitis could cause nasal congestion and lead to Eustachian tube dysfunction, explaining the ear symptoms.

Do Not Miss Diagnoses

• Nasopharyngeal Carcinoma: Although rare, this type of cancer can cause Eustachian tube obstruction, leading to the symptoms described. It's crucial to consider this diagnosis due to its potential severity and the need for early intervention.
• Temporal Bone Fracture or Trauma: Recent trauma to the head or ear could cause the symptoms described, including tinnitus and a feeling of fullness in the ear. This would be an emergency if there were signs of more severe injury.

Rare Diagnoses

• Patulous Eustachian Tube (PET): This condition involves the Eustachian tube staying open, which can cause autophony (hearing one's own breathing sounds) and could potentially lead to the sensation of being underwater when people talk, though it's less likely to cause nasal congestion.
• Meniere's Disease: An inner ear disorder that involves vertigo, tinnitus, hearing loss, and the sensation of ear fullness. While it could explain some symptoms, the nasal congestion and unilateral breathing difficulty are not typical presentations of Meniere's disease.
• Cholesteatoma: A type of skin cyst in the middle ear that can cause hearing loss, tinnitus, and a feeling of fullness. It's less likely given the absence of other typical symptoms like discharge or a history of recurrent ear infections.