CONDITION
Otitis Interna
Otitis interna describes inflammation within the inner ear, the deepest portion of the ear structure that houses the organs of hearing and balance. This area sits behind the eardrum and the middle ear, enclosed in bone, and when it becomes inflamed the signs tend to relate more to balance and coordination than to the kind of ear discomfort owners may associate with outer ear infections. Owners often arrive at this page because their dog or cat has developed a head tilt, seems unsteady on their feet, or is struggling with balance in a way that appeared quite suddenly. In some cases there may be a history of ear trouble, but in others the signs can seem to come from nowhere. The eyes may also show unusual movement, and the animal may seem reluctant to move or may circle in one direction. This page explores the patterns that can point towards inner ear inflammation, what may be happening beneath the surface to produce these signs, how the condition is investigated through examination and imaging, and the range of approaches that exist to address the underlying cause and support recovery. The structure is designed to help you understand what you may be observing and what shape the process of working through it might take.
Why this matters now
Otitis interna can appear at any age, though it tends to develop more often in animals with a history of chronic outer or middle ear disease, where infection or inflammation has progressed inward over time. Certain breeds with narrow or pendulous ear canals—such as Cocker Spaniels and Cavalier King Charles Spaniels—may be at somewhat higher risk, though the condition is seen across all breeds and in both dogs and cats. In some cases, particularly in younger animals, the inflammation may arise without any prior ear trouble, linked instead to spread of infection from the throat or bloodstream, or to less common causes such as polyps or tumours in the middle ear.
The signs of inner ear inflammation often appear quite suddenly, with balance disturbance and head tilt developing over a matter of hours to days. In cases where the cause is extension from a middle ear infection, there may have been a period of ear discomfort or discharge beforehand, though this is not always the case. The severity of signs can vary widely between individuals, with some animals remaining mobile but unsteady, whilst others may struggle to stand or show marked distress. Without intervention, signs may persist or worsen, though the natural course depends heavily on the underlying cause and whether that cause remains active.
Signals & patterns
Early signals
Head tilt to one side
The head may be held persistently tilted towards the affected ear, sometimes quite markedly. This posture reflects the disruption to the balance organs within the inner ear, which normally send continuous signals about head position.
Unsteady gait or veering
The animal may drift or lean towards one side when walking, or seem generally uncoordinated, as though the floor is uneven. This pattern arises because the brain is receiving conflicting or absent information about balance and spatial orientation.
Unusual eye movement
The eyes may flick rhythmically from side to side, or occasionally up and down, a pattern known as nystagmus. This movement is an automatic response to the inner ear's disrupted signals and can be quite noticeable, particularly when the head is still.
Reluctance to move or turn
Some animals become hesitant to walk or change direction, and may seem anxious or disoriented. The loss of reliable balance information can be profoundly unsettling, and the animal may prefer to stay in one position.
Circling in one direction
The animal may walk repeatedly in a tight circle, usually towards the side of the head tilt. This behaviour reflects the imbalance in vestibular input, with one side of the balance system effectively overpowering the other.
Later signals
Inability to stand or falling over
In more advanced cases, the disturbance to balance may be severe enough that the animal cannot maintain an upright posture and repeatedly falls towards the affected side. This tends to occur when the inflammation is more pronounced or when both the balance and hearing structures are involved.
Rolling or persistent recumbency
Some animals may roll continuously or lie on their side, unable to right themselves. This pattern suggests a profound loss of vestibular function and can be particularly distressing to observe.
Altered mental state or dullness
If the underlying cause has spread beyond the inner ear—such as infection reaching the bone or nearby nervous tissue—the animal may seem less responsive, confused, or generally unwell. This shift in behaviour can indicate a more complex or serious process.
Signs of pain around the head or ear
Though inner ear inflammation does not always produce obvious discomfort, some animals may show sensitivity when the head or ear is touched, or may seem reluctant to lower the head. This can occur when there is associated infection or pressure within the bony structures.
Click to read about the biological mechanisms
How this is usually investigated
Options & trade-offs
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