Cats can get all sorts of diseases that it makes you wonder how they managed to survive in the wild without someone opening cans of food for them. One disease that cats can get is called miliary dermatitis, which causes scratching or excessive licking excessively along with a possible crusty red rash.
Usually miliary dermatitis occurs from allergens, common from flea allergies. If you notice your cat licking itself or thinning on your cat’s coat, take your cat in to see the vet to check for this disease.