Middle ear abscesses occur as a complication of ear mite infection or barley grass seeds. Usually only a single ear in a single animal is affected but there may be multiple cases in sheep grazed on barley grass in summer. Signs are related to damage to the facial nerve as it passes through the middle ear.
There will be a head tilt and a drooping upper eyelid, and if inflammation extends internally, circling and incoordination result. Very rarely the infection extends to become a brainstem abscess resulting in death. Progression to death is not rapid like in listeriosis and an otoscopic examination might see pus from the abscess deep in the ear canal.
Antibiotic (procaine penicillin, or oxytetracycline) and anti-inflammatory (flunixin meglumine, or ketoprofen) treatment may delay or stop progression of signs, but resolution of head tilt and other nervous signs is usually not possible.
The usually sporadic occurrence of this condition does not warrant specific preventative measures.