Otitis Media with Tympanic Membrane Perforation: This condition is a common cause of mucous discharge from the ears in pediatric patients. The perforation of the tympanic membrane allows the infected mucous from the middle ear to drain out, presenting as a discharge.

External Otitis (Swimmer's Ear): This is an infection of the outer ear canal, which can cause a mucous discharge. It's common in children who swim frequently or insert objects into their ears.
Eustachian Tube Dysfunction: This condition can lead to a buildup of fluid in the middle ear, potentially causing a mucous discharge if the fluid becomes infected or if there's a perforation.
Allergic Rhinitis: Although not directly causing ear discharge, allergic rhinitis can lead to Eustachian tube dysfunction, which in turn might result in middle ear effusion and potentially discharge if the tympanic membrane is perforated.

Mastoiditis: This is an infection of the mastoid bone, which can spread from otitis media. It's a serious condition that requires prompt treatment to prevent complications such as abscess formation or intracranial spread.
Cholesteatoma: A type of skin cyst in the middle ear that can cause destruction of the surrounding bone and tissue, leading to complications like facial paralysis or hearing loss. It might present with chronic or recurrent mucous discharge.
Nasopharyngeal Carcinoma (rare in pediatrics but critical to consider): Although extremely rare in children, any persistent or unexplained symptoms like ear discharge should prompt a thorough investigation to rule out serious conditions.

Branchial Cleft Cyst or Sinus: Congenital anomalies that can present with discharge, although typically not from the ear itself but potentially mistaken for ear discharge if the opening is near the ear.
Middle Ear Tumors: Benign or malignant tumors in the middle ear are rare and can cause a variety of symptoms including hearing loss, tinnitus, and potentially discharge if they obstruct the Eustachian tube or cause a perforation.