The answer to 'why is my flea damage' is that you likely have a flea infestation in your home. Fleas are small, wingless insects that feed on the blood of warm-blooded animals, including pets and humans. They can cause a range of problems, from itchy bites to the transmission of diseases.
Some common causes of flea damage include pets bringing fleas into the home, or fleas finding their way in through cracks and crevices. Symptoms of a flea problem include seeing the fleas themselves, finding flea dirt (their fecal matter) on your pets or in your home, and excessive scratching or irritation in your pets.