When a cat has ear mites a dark brown waxy discharge can be seen when you look in the cat’s ears which looks like coffee grounds and which MAY BE FOUL SMELLING. The answer to the question in the title is that the presence of ear mites in a cat’s ears may cause the ears to smell. In addition to the waxy discharge there may be cellular debris and a possible chronic bacterial infection caused by the cat constantly scratching due to intense itching.
Although a veterinarian will diagnose ear mites by removing some ear wax with a cotton tip applicator and examining it under a microscope to look for tiny white, moving specks, if both ears have a waxy discharge as described above, suspect ear mites. The strong advice from vets is not to treat ear mites until there has been a positive identification from your veterinarian. The reason is (1) you can make things worse and (2) ear mite medications can cause other ear health issues. You need to know what you are doing.
Ear mites are highly contagious and they leave the ear canal to infect other parts of the body and other cats or kittens. Kittens can be infected by their mother while in the maternal nest.
Speed is important in treating cat ear mites for the simple reason that your cat will be in considerable discomfort and as mentioned they are contagious. You don’t want your other cat or cats to get them (if you have a second or third cat) and you don’t want your cat or cats to be in acute discomfort and/or self mutilate themselves by scratching.
SOME MORE ON EAR MITES: