This is not a symptom of Boxwood Blight, however it does look like Volutella Blight. You can read more about in on the link provided. You can prune out the dead/dying branches and many times boxwood will rebound from this. The bottom of the link has a boxwood pruning video for guidance. They will look sparse for a few years until they grow back in so if that is not a look you are ok with since it looks like the front of your home, then you may want to consider replacing them. While no plant is disease proof there are new cultivars of boxwood that have better disease resistance than others. Look for varieties such as 'New Gen' 'Green Velvet' 'Green Mountain' or any that state they have better disease resistance.

Emily