The symptoms of external parasites in cats mainly include the following aspects:

1. Dry hair with black particles on the hair: The cat’s hair is very dry and dull, and there are also small black particles on the hair. Granules, if you dissolve these small black granules in water, blood will appear, indicating that the cat has external parasites.

2. White gums and anemia: A healthy cat has pink gums. If your cat's gums are white, it is most likely anemia due to parasite infection.

3. Swollen belly and thin body: The cat has a swollen belly but a very thin body. It eats a lot but does not gain weight. Instead of gaining weight, it loses weight. This is one of the signs that the cat is suffering from "parasites".

4. Vomiting, diarrhea and coughing: Cats occasionally have vomiting and diarrhea. This is normal, but if the cat Vomiting and diarrhea occur more frequently, along with symptoms such as coughing and shortness of breath. The cat may be infected with worms and heartworms.

5. The feces contain parasites or bloodshot eyes: When a cat is infected with parasites, the parasites will be excreted when the cat defecates. When you find worms or blood streaks in your cat’s poop, it means your cat has been infected with parasites.

6. Rubbing their buttocks and scratching their ears and cheeks: Cats often rub their buttocks and scratch their ears and cheeks. Cats may be infected with parasites, which causes anal itching, so they want to rub their buttocks to relieve the itching. In addition to rubbing its butt, the cat will frequently scratch its ears and lick its body in various ways. There should be fleas on the cat's body.

The above are some symptoms of external parasites in cats. If a cat is found to have these symptoms, it is recommended to take the cat to the veterinarian in time and receive corresponding deworming treatment. At the same time, you should also pay attention to the cat’s living environment and dietary hygiene to prevent the cat from being infected with parasites again.