People who have lupus and systemic vasculitis have weakened immune systems that are more susceptible to infections. Side effects of medication intended to help manage these diseases, specifically steroids and chemotherapeutics, can weaken the immune system further.

Specifically, they are at an increased risk for varicella-zoster virus (VZV) reactivation. VZV is the virus, which can cause chickenpox (varicella) and shingles (zoster). Once a person recovers from chickenpox, VZV remains inactive in the body. VZV can reactivate and cause a painful rash called shingles. There are many reasons why the virus can reactivate.