The experts say that the gluten molecule is too large to pass through skin, so lotions, shampoos, conditioners, and other external products shouldn’t be a problem unless you have open sores, rashes, or dermatitis herpetiformis.
Sometimes lotion from your hands or arms can get on the food you’re eating or preparing, and that can cause a problem. Be sure to wash your hands well (along with any other area that may touch food), so you don’t end up eating your lotion.
In spite of the scientific evidence suggesting external products shouldn’t pose a problem, some people report reactions to products they touch or apply that contain gluten. The simplest advice: If a product bothers you, don’t use it.