Fleas and ticks can cause a wide variety of issues for your cats and the most common of which is flea bite dermatitis – a specific allergy to flea saliva. It leads to intense itching and scratching, then make your cats’ skin break open and form scabs that can get infected. Moreover, fleas and ticks are also the health risk to humans. Although they don’t actually live on your skin or hair, they still bite you, which carries certain diseases, such as: plague and cat scratch fever.