The cat skin differs from the dog skin in its thickness and pH level. Namely, cat skin is much thinner and more acidic than dog skin. The short answer is a cat’s skin is simply more sensitive than a dog’s. So, although the dog’s and cat’s skin serve the same purpose, they are not the same and cannot be bathed with the same products. Namely, if cat owners use shampoos made for dogs, chemicals can easily get absorbed through the skin. Plus, the dog shampoo can dry the cat’s skin.