What precautions should be taken if a relative has zoster sine herpete and another relative is not vaccinated with the varicella (chickenpox) vaccine?

Precautions for Zoster Sine Herpete Exposure in Unvaccinated Household Members

Understanding Transmission Risk

Zoster sine herpete (ZSH) presents minimal to no transmission risk because there are no skin lesions containing infectious viral particles, making standard isolation precautions unnecessary. 1

The key distinction is that ZSH is VZV reactivation without the characteristic vesicular rash—meaning there are no fluid-filled lesions that contain transmissible virus particles. 1 Unlike typical herpes zoster where vesicular fluid contains enormous amounts of virus particles that can transmit to susceptible individuals and cause varicella (chickenpox), ZSH manifests only as neuralgia or other neurological symptoms without cutaneous lesions. 2, 1

Risk Assessment for the Unvaccinated Relative

If the unvaccinated relative has prior chickenpox history:

• No precautions are needed and no activity restrictions are required. 3
• Prior varicella infection provides immunity, eliminating transmission concerns even with typical zoster exposure. 4

If the unvaccinated relative has no history of chickenpox and is immunocompetent:

• No isolation or avoidance measures are necessary for ZSH specifically, since there are no infectious skin lesions. 1
• Consider varicella vaccination for future protection against primary VZV infection from other sources. 3
• The relative should avoid exposure to persons with active chickenpox or typical shingles (with visible lesions) from other sources. 4

If the unvaccinated relative is immunocompromised:

• Even with ZSH, immunocompromised individuals should maintain general precautions against VZV exposure from any source. 4
• Post-exposure prophylaxis with varicella-zoster immune globulin (VZIG) at 1 mL/kg should be administered within 96 hours only if there was documented exposure to typical zoster with uncovered lesions or to chickenpox—not applicable to ZSH. 4
• Household contacts of immunocompromised persons should receive varicella vaccination if they lack immunity to prevent them from becoming a transmission source. 4

Practical Management Algorithm

1. Confirm the diagnosis is truly ZSH (no rash present, only neurological symptoms). 1

2. Assess the unvaccinated relative's immunity status:

   • History of chickenpox = immune, no precautions needed 3
   • No history of chickenpox = susceptible, but still no precautions needed for ZSH specifically 1

3. Assess immunocompromised status:

   • If immunocompromised: general VZV avoidance strategies regardless of ZSH 4
   • If immunocompetent: no special precautions for ZSH 3

4. Consider varicella vaccination for the susceptible relative for future protection (not as post-exposure prophylaxis for ZSH, but for general immunity). 3

Important Clinical Caveats

• The absence of rash in ZSH means there is no viral shedding from skin lesions, which is the primary transmission route for VZV. 1
• Transmission of VZV from typical herpes zoster occurs through direct contact with vesicular fluid; airborne transmission is rare and primarily associated with disseminated zoster or varicella. 4, 2
• If the person with ZSH later develops a rash, the diagnosis should be reconsidered as typical herpes zoster, and standard contact precautions should be implemented until all lesions crust. 4, 3
• Household contacts should receive varicella vaccination to protect both themselves and immunocompromised household members from becoming inadvertent transmission sources. 4