Infection: Shingles; zoster; herpes zoster; varicella zoster virus (VZV) reactivation
Brief description:
Caused by reactivation of VZV (same virus as chicken pox), with characteristic painful rash in a dermatomal pattern.
Did you know?
Vaccination is funded in NZ in those aged 65 years. This is regardless of whether they recall a history of chicken pox, and serology to check is not recommended.
Who should I test?
- Laboratory testing is not usually required. The diagnosis is made clinically in the vast majority of people due to the characteristic nature of the rash.
- Laboratory testing is reserved for atypical cases where there is diagnostic uncertainty.
- We recommend HIV testing in people with recurrent or atypical presentations of shingles, including shingles occurring in young people.
Test of choice:
Request VZV PCR
Viral swab of rash for VZV PCR (need to obtain fluid or cellular material on swab)
- Good sensitivity – a negative result on an adequately collected sample makes the diagnosis very unlikely
- Excellent specificity – a positive result confirms the diagnosis
Note: swabs run for VZV PCR in our laboratory are run for HSV PCR in parallel, as these viruses can mimic each other.
Tests to avoid/specialist tests:
This has no role in the diagnosis of shingles due to the fact shingles is caused by reactivation of a virus already present in the body.