These are not symptoms of Boxwood Blight, but they do look like symptoms of Volutella Blight (a different fungus that we see more often), and possibly overlapping winter damage. You can learn about both diseases (and common pest or other problems) on our boxwood diagnostic page.

Nothing can cure diseased wood, or reverse its symptoms. Dead branches need to be pruned off, and in cases of severe damage, it is usually more practical to remove and replace the plant unless you can wait several years for a heavily-pruned plant to regrow to its former size. Volutella Blight doesn't kill roots, so assuming no other issue has impacted their health, the shrub might recover if it is pruned way back, leaving only a few inches of stem base on most or all of the branches. Boxwood growth is naturally slow, so it may only regrow a few inches worth this year. Avoid shearing boxwoods (pruning them into dense, manicured shapes with hedge shears) as this increases their vulnerability to problems like blight infections.

Some boxwood cultivars have better resistance to certain pests and diseases than others, but few (if any) variegated forms have high resistance to these fungal diseases as well as Boxwood Leafminer, a common and damaging insect pest.

Miri