Fleas don’t just stay on your dog. They can also be found all through your house, and especially in areas where your dog spends a lot of her time. Closely examine your dog’s feeding area, bedding, and her favorite locations for signs of flea dirt (black specks), or for the fleas themselves.
Another method you can use to search for flea dirt in the house is to wear white socks and walk through areas frequented by your dog. Fleas and/or flea dirt may be picked up by the fibers of the socks and will stand out on the white background.
Another method, called a "light trap," may also help detect the presence of fleas in the household. At night, before all the lights have been turned off, 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 dog or in your living environment, or if you have done the full flea eradication treatment on your dog and home but your dog is still scratching excessively, it’s time to ask your veterinarian for advice. He or she will help you determine the cause of your dog’s discomfort and suggest treatment options.