Why cats scratch their ears with their paws:
1. Cats scratching their ears is a habit, and it may be a sign of happiness or anger. As long as no obvious foreign objects are found in its ears, there is no need to worry too much.
2. It could be caused by ear mites. If there is dark brown discharge in the ear canal, then it is ear mites, and you need to treat your cat regularly with ear cleaning solution.
3. It could be caused by ringworm. If there is redness, swelling, hair loss, dandruff, or scabs around the ears, then it is ringworm. You can apply antifungal medication to the affected area. 
Symptoms of ear mites in cats:
1. Itching: Once a cat has ear mites, its ears will itch unbearably. It will constantly scratch its ears or shake its head and rub its head against the floor. If you find that your cat has these symptoms, it may have ear mites.
2. Abnormal earwax color: If the cat's earwax is dark brown or black and waxy, and is not easy to clean, it can generally be determined that it has ear mites.
3. Unpleasant odor from the cat's ears: Healthy cat ears have no odor, while cats with ear mites have a particularly unpleasant sour smell from their ears. In severe cases, you can smell it when you get close to the cat. In this case, the cat's ear mites are already quite serious.
