Otitis Externa: This condition, also known as swimmer's ear, is characterized by inflammation of the external auditory canal, which matches the patient's symptoms of ear pain, discharge, and edema of the external auditory canal, along with tenderness of the tragus.

Foreign Body in the Ear: Although less likely given the acute onset of discharge and edema, a foreign body could cause irritation and infection leading to similar symptoms.
Otitis Media: While more commonly associated with middle ear infection, otitis media could potentially cause external symptoms if there is associated external ear canal infection or if the patient has a perforated eardrum allowing middle ear discharge to exit through the external canal.

Labyrinthitis: Although less common, labyrinthitis (inflammation of the inner ear) is a serious condition that could present with ear pain and potentially discharge if there is associated middle ear infection. It's crucial to diagnose and treat promptly to prevent long-term hearing and balance issues.
Middle Ear Effusion with Perforation: A middle ear effusion (fluid behind the eardrum) that becomes infected and perforates could lead to discharge. This condition requires prompt treatment to prevent complications.

Malignant Otitis Externa: A rare but serious infection of the external auditory canal that can spread to surrounding bone and tissue, more commonly seen in diabetic or immunocompromised patients.
Relapsing Polychondritis: A rare autoimmune disorder that can cause cartilage inflammation, including the cartilage of the ear, potentially leading to ear pain and discharge, though this would be an unusual initial presentation.
Necrotizing Otitis Externa: A severe form of otitis externa that can lead to significant tissue destruction, more commonly seen in diabetic or immunocompromised patients.