How Do I Know If My Dog Is Allergic To Shampoo?

How Do I Know If My Dog Is Allergic To Shampoo? Discomfort and/or itchiness. Bald patches. Blister-like lesions. Chronic ear infections. Chronically inflamed feet. Face rubbing. Head shaking. Hives. How can I tell if my dog is having an allergic reaction? Clinical signs seen most commonly with this are redness of skin itself, itchiness, or