Ear disease will sometimes be called otitis by your vet. Ear disease rarely goes unnoticed when it is severe. Cats with ear problems will generally shake their head from side to side, and may be forever stopping to sit down and scratch their ears. In many types of infection there is a smelly discharge or the ear canal may be full of black wax. Sometimes, cats with sore ears will just sit with their head tilted to one side.
You should never put anything into your pet's ear unless you have been instructed to do so by your vet. Poking cotton wool buds or other cleaning devices into the ear canal can push debris or foreign bodies further down where they can cause serious damage.
Sometimes a cat with ear disease will shake their head so much that they burst a blood vessel and develop a swelling in their ear flap - a haematoma. If this happens your cat will probably need an operation to drain the swelling.