These external parasites invade the ear and cause itchiness, redness, and sometimes, severe infection. You may not be able to see the individual mites, but you may see a dark discharge in your cat's ear. If your cat shakes or scratches his or her ears persistently, take to your vet for cleaning and ear drops. The drops kill the adult mites, but not their eggs, so use the drops for the whole timespan the vet recommends to eradicate the problem. Treat all cats and dogs in your household, as mites are very contagious.

dog and cat ear mites.