Read original post by Muhammad Afzal at Getting Deep into .net Blog
In my recent consulting assignment I was asked the question by one of the developer , that how can we get dynamic theming working in Prism application. My answer was that you can implement in the same manner as you do in the standard Silverlight application. But then he further asked that there are various regions in the RegionManager and how each views loaded in the different content regions can get unified theme , this encouraged me to try this out and see how it works.I started working on it and viola my answer was correct , there is no difference in implementing dynamic theming in prism specific app.