There are a few reasons why some with Celiac Disease react to rice.
Essentially, when your body creates antibodies against gluten, those same antibodies also recognize and potentially attack proteins in other food that have a similar structure. The protein in rice is one such example for some. It is called cross reactivity.
The other possible reason is called cross contamination. Wheat/gluten can end up in rice during any stage of the production process.
Celiac causes intestinal permeability also simply known as leaky gut. When you have things floating around in your bloodstream that don’t belong there, it creates an over active immune system which triggers inflammation. That means until your gut is healed properly, you could potentially react to many different foods.
Watch my masterclasses on Gut health and How food Sensitivities begin to learn more on this topic.