Hello Hayley,
Your cat could suffer from several things:
1. If the hair around the area comes out easily and the skin is red and scaly, she could have ringworm. Ringworm is transmittable to other animals as well as humans but as long as you wash your hands after handling the cat, you should be fine. A simple fungal culture at your local vet can verify if your cat has ringworm. Usually fulvicin is used orally but you can use topicals such as Lamasil as well.
2. Mats can be groomed out by your cat leaving smooth, hairless patches. In this case there is nothing wrong but the cat may need more grooming. Use a long-tooth metal comb NOT a brush.
3. Your cat may have fleas. Excessive scratching and licking can cause hair loss due to flea allergy. If you see a black, peppery substance after rubbing your cat's hair coat (against the grain) while standing your cat on a white or light colored sheet or background, she has fleas. Please use a veterinary approved topical flea medication such as Advantage. I've seen too many cats have severe reactions and even death from over the counter flea medications such as Control and Hartz.
Cat's very rarely get mites and those mites wouldn't be transitable to humans in any case.
Hope this helps!