Check the Environment
Fleas don’t just stay on your cat. They can also be found throughout the house and in areas where your cat spends a lot of his time. Closely examine your cat’s feeding area, bedding, and other favorite locations for signs of flea dirt (black specks), or for the fleas themselves. As you know, cats like to sleep on top of things like the window sills, kitchen cabinets and refrigerator, so be sure to get up high when examining their favorite haunts.
Another method to search for flea dirt in the house is to wear white socks and walk through areas frequented by your pet. Fleas and/or flea dirt may be picked up by the fibers of the socks and will stand out on the white background.
A "light trap" may also help detect the presence of fleas in the household. At night, before turning off all the lights for the night, set a small bowl of water with dishwashing soap near a nightlight on the floor. Fleas will tend to jump toward the light and will fall into the bowl, where they will drown. In the morning, you may find several floating in the water.
Get a Veterinarian’s Advice
If you can’t find any signs of actual fleas on your cat or in the environment, or if you have done the full flea eradication treatment on your cat and home but your cat is still scratching, it’s time to get advice from your veterinarian. He or she will help you determine the cause of your cat’s discomfort and suggest treatment options.
The area between the abdomen and thighs; the inguinal area