Differential Diagnosis for Draining through Left Ear

• Single most likely diagnosis
  • Otitis media with perforation: This is the most common cause of drainage from the ear, especially if the patient has a history of ear infections or recent upper respiratory tract infection. The perforation of the tympanic membrane allows pus to drain out, which is a hallmark of this condition.
• Other Likely diagnoses
  • Otitis externa: Also known as swimmer's ear, this condition involves an infection of the outer ear canal. It can cause discharge, which might be mistaken for drainage from the ear itself. The discharge in otitis externa is often accompanied by itching, redness, and swelling of the outer ear.
  • Mastoiditis: This is an infection of the mastoid bone, which is located behind the ear. It can cause drainage if the infection spreads to the ear canal or if there is a perforation of the eardrum. Mastoiditis often presents with symptoms such as fever, headache, and tenderness behind the ear.
  • Eustachian tube dysfunction: While not typically causing frank drainage, severe Eustachian tube dysfunction can lead to middle ear effusion, which might occasionally drain through a perforated eardrum or through other abnormal pathways.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Cerebrospinal fluid (CSF) leak: A leak of CSF through the ear can occur due to a fracture of the temporal bone or other trauma. This condition requires immediate medical attention to prevent meningitis. The drainage in CSF leaks is often clear and can be distinguished from infectious discharge by its appearance and the presence of glucose.
  • Necrotizing otitis externa: A severe form of otitis externa that can spread to the skull base and cause significant morbidity and mortality, especially in diabetic or immunocompromised patients. It presents with severe pain out of proportion to the appearance of the infection.
• Rare diagnoses
  • Cholesteatoma: A type of skin cyst located in the middle ear that can cause destruction of the surrounding bone and tissue, potentially leading to drainage. Cholesteatomas are rare and often present with a history of recurrent ear infections or a sensation of fullness in the ear.
  • Labyrinthine fistula: An abnormal connection between the inner and middle ear, which can cause drainage of inner ear fluids. This condition is rare and often associated with congenital anomalies, trauma, or chronic ear disease.
  • Petrous apicitis: An infection of the petrous part of the temporal bone, which can cause a variety of symptoms including drainage from the ear. This condition is rare and can be life-threatening if not properly treated.