Cats will endure many medical issues throughout their life but some are more common than others. Ear mites is one of those that you will see more often than not.
There is an estimated 90% of cats each year will be come infested with ear mites so if you observe your cat constantly shaking his head, digging at his ears, or a strange odor coming from his ears its possible this is the cause of all their problems. Ear mites are contagious and may spread to other cats in your household. These are small crab-like parasites that house themselves inside the cats head or ear canal and possibly in other areas of the body. Ear mites feed on your cats tissue fluids and tissue debris but can also spread to the skin infecting it.
All cats can become infested but its more common to see in young cats or kittens because their immune system has not had a chance to build itself up yet. Mites normally have a 3 week cycle and can survive for many weeks and unlike fleas they do not suck blood or pierce the skin.
Things you will need to watch for is skin lesions, shaking or excessive scratching, and ear discharge that can be either crusty or black. Your veterinarian will clean and medicate your cats ears after confirming that ear mites is the issue.