If your cat is itching, you should check for fleas which can cause anemia from blood loss (also check for tapeworms in kittens). While there are cat and dog fleas, the cat flea is found in the US among dogs, cats and people, while the dog flea is found primarily in Europe.
When the temperature is 65+ and the humidity is 75+, fleas are in season. While tiny, you can see them or “flea dirt” which looks like dark specks. Unfortunately, if your cat has fleas, it is likely that you may have fleas as well in your home or yard. You will need to remove them from all areas.
There are prescription products for your pet that control the hatching of the eggs which can be more effective, but you will also need to address your home and yard (if you have a lot of fleas). Ask your veterinarian what they recommend.
There are four stages of fleas: eggs, larvae, pupae and adults and the total of these stages last 14 to 75 days. They can live for a year as fully formed larvae until conditions are right for them to emerge (heat, vibrations and exhaled carbon dioxide). Adult fleas, that live 4-25 days, require fresh blood to produce eggs and that is when they live on your pet (and maybe you).