Differential Diagnosis for a Knot Behind the Ear
Single Most Likely Diagnosis
- Lymphadenopathy: This is the most common cause of a knot behind the ear, often due to a viral or bacterial infection, and can be accompanied by other symptoms such as fever, sore throat, or ear pain.
Other Likely Diagnoses
- Mastoiditis: An infection of the mastoid bone, which is located behind the ear, can cause a knot or swelling in this area, often accompanied by ear pain, fever, and discharge.
- Cyst or Abscess: A sebaceous cyst or abscess can form behind the ear, causing a palpable knot, and may be tender to the touch.
- Lipoma: A benign fatty tumor can grow behind the ear, presenting as a soft, movable knot.
Do Not Miss Diagnoses
- Meningitis: Although less common, a knot behind the ear can be a sign of meningitis, especially if accompanied by symptoms such as fever, headache, stiff neck, and confusion.
- Temporal Arteritis: Inflammation of the temporal artery can cause a tender knot or swelling behind the ear, and is a medical emergency if not promptly treated.
- Parotid Gland Tumor: A tumor of the parotid gland, located near the ear, can cause a knot or swelling in this area, and requires prompt evaluation.
Rare Diagnoses
- Branchial Cleft Cyst: A congenital anomaly that can cause a cyst to form behind the ear, presenting as a knot or swelling.
- Neurofibroma: A benign tumor of the nerve tissue can grow behind the ear, causing a knot or swelling, and may be associated with neurofibromatosis.
- Metastatic Cancer: In rare cases, a knot behind the ear can be a sign of metastatic cancer, such as from a primary tumor in the head or neck region.