Differential Diagnosis for Right-Sided Ear Pain

The patient presents with right-sided ear pain, itchiness, erythema, and mild crusting on the exterior of the ear, without fluctuance, but tender to palpation. Based on these symptoms, the differential diagnosis can be categorized as follows:

• Single Most Likely Diagnosis
  • External Otitis (Swimmer's Ear): This condition is characterized by inflammation of the outer ear and ear canal, often caused by bacterial or fungal infections. The symptoms of ear pain, itchiness, and mild crusting, along with the physical exam findings of erythema and tenderness to palpation, align closely with external otitis. The absence of fluctuance makes a more severe infection like an abscess less likely, but it does not rule out the possibility of an early or mild infection.
• Other Likely Diagnoses
  • Eczema/Dermatitis: Eczema or dermatitis of the ear can cause itchiness, erythema, and crusting, similar to the patient's symptoms. This condition could be a primary skin issue or secondary to an allergic reaction.
  • Psoriasis: Psoriasis can affect the ear, leading to erythema, scaling, and sometimes itchiness. While less common than external otitis, it should be considered, especially if the patient has a history of psoriasis.
  • Seborrheic Dermatitis: This condition can cause a red, itchy, and flaky rash on the ears, among other areas. It's a common condition that could explain the patient's symptoms.
• Do Not Miss Diagnoses
  • Malignancy (e.g., Squamous Cell Carcinoma): Although rare, skin cancers can present with similar symptoms, including erythema, crusting, and discomfort. Given the patient's age, it's crucial not to miss a potential malignancy.
  • Necrotizing Otitis Externa: This is a severe infection that can occur, especially in diabetic or immunocompromised patients. It presents with severe pain out of proportion to the physical findings and can lead to significant complications if not promptly treated.
  • Herpes Zoster (Shingles): Herpes zoster can affect the ear, causing pain, erythema, and vesicles. It's essential to consider this diagnosis, especially if the patient has a history of herpes zoster or is immunocompromised.
• Rare Diagnoses
  • Relapsing Polychondritis: This is a rare autoimmune disorder that can cause cartilage inflammation, including the cartilage of the ear. It might present with ear pain, redness, and swelling.
  • Granulomatosis with Polyangiitis (formerly Wegener's Granulomatosis): This rare autoimmune disorder can affect various parts of the body, including the ears, and might present with similar symptoms, although it would be an unusual initial presentation.

Each of these diagnoses should be considered based on the patient's full clinical picture, including history, physical examination, and potentially, further diagnostic testing.