What causes hair loss on a cat?

i have a 6 year old cat she stays inside for the past 2 weeks she has been digging at her face and neck, she has really bad sores and is almost bald on her face and neck, does anyone know what might be wrong with her?i changed her food recently she is itching really bad and her sores look terrible ive tried peroxide but it seems to make it worse. if anyone has any information that will be helpful i would greatly appreciate it.What causes hair loss on a cat?
It could be almost anything. She could have fleas, mites, or some other sort of parasite. She could have come in contact with something poisonous, like a plant or a cleaner. She could have allergies to just about anything from food to mold or fragrances in her litter box. She could have a medical condition, it's really hard to say why.





I would take her to the vet ASAP, regardless of what you might think is wrong. Do not use anything on her until you see the vet. Peroxide will make it worse, so stop using that on her. It is not a good idea to provide home care when there are so many different things it could be, both external and internal.





I'm not sure what she has been eating or what you are feeding her now, but stay away from foods with corn, wheat, soy, or by-products. These ingredients are terrible for cats, especially if a food allergy is suspected.What causes hair loss on a cat?
You should definitely take her to the vet. Sounds like allergies, fleas or ear mites. All need help from a vet. If she wasn't scratching before the food change, switch her back and get her to the vet to be looked over. They can also give her something to help with the itching.
More or less its an allergy and you should change her food back to the original and just to assure yourself take her to the vet.
Could be fleas.

liquid eye liner