Is zoster sine herpete (shingles without rash) on the lips and tongue contagious, especially to individuals who have not had varicella (chickenpox) or have weakened immune systems?

Is Zoster Sine Herpete on Lips and Tongue Contagious?

Zoster sine herpete (ZSH) is theoretically contagious to susceptible individuals (those without prior chickenpox or vaccination), but the transmission risk is extremely low to negligible because there are no visible vesicular lesions containing viral particles that could be transmitted through direct contact. 1, 2

Understanding Zoster Sine Herpete

• Zoster sine herpete represents VZV reactivation that causes dermatomal pain and other neurological symptoms without the characteristic vesicular rash 1, 2
• The diagnosis is challenging and requires laboratory confirmation through VZV DNA detection or anti-VZV antibody testing (IgG and IgM) 1
• ZSH can affect cranial nerves, spinal nerves, viscera, or autonomic nerves, causing variable symptoms including neuralgia, Bell's palsy, and Ramsay Hunt syndrome 1

Transmission Risk Assessment

The practical contagiousness of ZSH is minimal because transmission of varicella-zoster virus requires direct contact with fluid from vesicular lesions or, rarely, inhalation of aerosols from these vesicles 3, 4

• Standard herpes zoster (with rash) transmits VZV through direct contact with vesicular fluid or through airborne aerosols from active lesions 3, 4
• Without visible vesicles, there is no vesicular fluid available for transmission through the typical contact route 5, 1
• The virus particles that cause transmission are present in enormous amounts in vesicle fluid, which is absent in ZSH 5

Critical Distinction from Standard Shingles

• Regular herpes zoster remains contagious from 1-2 days before rash onset until all lesions are completely dry and crusted (typically 4-7 days after rash onset) 4
• Localized shingles with visible lesions is approximately 20% as contagious as chickenpox, but still poses measurable transmission risk through direct contact 4
• Airborne transmission of standard shingles has been documented in healthcare settings, particularly affecting immunocompromised patients 4

Practical Recommendations for ZSH

No special isolation precautions are required for patients with confirmed zoster sine herpete, as there are no lesions to transmit virus 3, 4, 1

• Standard hygiene practices (handwashing with soap and water) are sufficient 4
• No work restrictions are necessary for healthcare workers or other professionals with ZSH 4
• Contact with high-risk individuals (pregnant women, immunocompromised persons, neonates) does not require avoidance in ZSH cases 3, 4

Important Caveats

• The critical pitfall is misdiagnosis: ensure the patient truly has ZSH and not early-stage herpes zoster before visible lesions appear, as standard shingles becomes contagious 1-2 days before rash onset 4, 1
• If any vesicular lesions develop (even subtle ones on mucous membranes), the patient should immediately be considered contagious and standard contact precautions implemented 3, 4
• Immunocompromised patients with ZSH may have atypical presentations and should be monitored closely for development of lesions or disseminated disease 4, 5
• Early antiviral treatment (within 24 hours of symptom onset) is still recommended for ZSH to prevent complications like postherpetic neuralgia and VZV encephalitis, even though transmission risk is minimal 1, 2