Can extended sciatica bring on shingles?

Sciatic and shingles: Yes, i believe that any stressors (physical, emotional...) can bring about shingles. It's important to diagnose and treat both appropriately.

Yes: Any chronic stressor (like pain) can cause shingles to occur.

No: Most likely the shingles was acting up bringing on pain and then the rash/blisters showed up. Occasionally you can have both shingles and sciatica at the same time, but that is highly unlikely.

Remember shingles: is a reactivation of chickenpox. In times of stress which can include the pain of sciatica your body can react be reactivating the virus. Important to treat it as your biggest concern is postherpetic neuralgia which is the pain that can be associated with the rash. I recommend oral antivirals and LED light for pain