Differential Diagnosis for Bilateral Ear Canal Itching and Irritation

Single Most Likely Diagnosis

• External Otitis (Swimmer's Ear): This condition is characterized by inflammation of the external ear canal, often caused by bacterial or fungal infections, and is common in young adults. The patient's symptoms of bilateral ear canal itching, irritation, and redness, along with the appearance of the external ear canal on exam, align closely with external otitis.

Other Likely Diagnoses

• Allergic Contact Dermatitis: This could be due to an allergic reaction to earbuds, earrings, or ear drops, leading to itching and redness in the ear canal.
• Eczema (Atopic Dermatitis): Individuals with atopic dermatitis can experience eczema in the ear canal, leading to itching and irritation.
• Seborrheic Dermatitis: This condition can cause a red, itchy rash on various parts of the body, including the ears, and could potentially involve the ear canal.

Do Not Miss Diagnoses

• Malignant Otitis Externa: Although rare, this condition is a severe infection of the external ear canal that can spread to surrounding bone and tissue, particularly in diabetic or immunocompromised patients. It requires prompt recognition and treatment.
• Relapsing Polychondritis: An autoimmune disorder that can cause cartilage inflammation, including in the ears, leading to redness, pain, and potentially destructive lesions if not treated.

Rare Diagnoses

• Keratosis Obturans: A condition where desquamated skin accumulates in the ear canal, potentially causing itching, irritation, and sometimes hearing loss.
• Ear Canal Cholesteatoma: An abnormal skin growth in the middle ear behind the eardrum, which can be asymptomatic for a long time but may cause itching and irritation if it involves the ear canal.