what is causing my cat to scratch his ear?
Cats Scratching Ears with Parasites. If this is not the issue, then it may be related to parasites alone. Check your cat's ears for signs of ticks, fleas, and mites. These parasites can cause obsessive scratching, as the cat makes a desperate effort to relieve pain and discomfort. If your cat is not allergic, try using natural tick or flea repellents (or mite repellent) if that seems to be the issue.