Otitis Externa: This is the most common cause of ear discharge, especially in the context of ear pain, itching, and a history of swimming or trauma to the ear canal. The discharge is often purulent and may be accompanied by a foul odor.

Otitis Media: This condition, particularly when it is suppurative, can cause ear discharge, especially in children. The discharge may be serous or purulent and is often associated with ear pain and fever.
Eustachian Tube Dysfunction: This can lead to a middle ear effusion, which may cause a serous discharge, especially if the eardrum is perforated.
Chronic Suppurative Otitis Media (CSOM): A condition characterized by a chronic infection of the middle ear cleft, often associated with a perforated tympanic membrane and persistent purulent discharge.

Malignant Otitis Externa: Although rare, this condition is a severe infection of the external auditory canal that can spread to surrounding bone and tissue, particularly in diabetic or immunocompromised patients. It requires prompt recognition and treatment to prevent serious complications.
Cerebrospinal Fluid (CSF) Leak: A condition where there is an abnormal communication between the subarachnoid space and the external environment, which can present with clear ear discharge. This is a medical emergency due to the risk of meningitis.
Necrotizing Otitis Media: A severe form of otitis media that can lead to significant complications, including cranial nerve palsies and death if not promptly treated.

Relapsing Polychondritis: A rare autoimmune disorder that can cause inflammation of the cartilage in the ear, leading to ear discharge among other symptoms.
Keratosis Obturans: A condition where desquamated skin accumulates in the ear canal, potentially causing discharge and other symptoms.
Cholesteatoma: An abnormal skin growth in the middle ear behind the eardrum, which can cause chronic discharge and hearing loss. It is a rare condition but can have serious implications if not treated.