Cats that have fleas are often very itchy and may have hair loss, skin redness, and even scabs. The hair loss is often most prevalent at the base of the tail but can occur anywhere. Flea dirt, which is the black flea feces, can be seen in the fur. It can be differentiated from regular dirt by putting some of it on a wet cotton swab and rubbing it in. Since flea dirt is composed of digested blood, if it turns red on the wet cotton swab, it is probably flea dirt. If it is simply black, it’s probably just dirt from outside. A flea comb can be used to try and catch a live flea but some cats will have fleas and you won’t see live ones because cats are such fastidious self-cleaners.