Can zoster sine herpetica (shingles without a rash) occur on the lips and tongue, particularly in individuals with a history of varicella-zoster virus infection?

Zoster Sine Herpete Can Occur on Lips and Tongue

Yes, zoster sine herpete (varicella-zoster virus reactivation without the characteristic rash) can affect the lips and tongue, though this represents an atypical presentation that requires laboratory confirmation for diagnosis.

Understanding Zoster Sine Herpete

Zoster sine herpete occurs when VZV reactivates in sensory ganglia but produces neurological symptoms without the dermatomally distributed vesicular rash 1. This condition can affect any cranial nerve distribution, including the trigeminal nerve branches that innervate the oral cavity 2.

Anatomical Distribution in the Oral Region

Trigeminal Nerve Involvement

The trigeminal nerve branches can be affected by VZV reactivation, with specific patterns:

• Maxillary branch (V2) involvement can produce lesions on the hard palate, soft palate, and upper lip 3
• Mandibular branch (V3) involvement, though rare, can affect the tongue, lower lip, and oral mucosa 4
• The nasopalatine and infraorbital nerves (branches of V2) are responsible for oral cavity involvement when affected 3

Clinical Presentation Without Rash

In zoster sine herpete affecting oral structures, patients may present with:

• Isolated pain in the distribution of affected cranial nerves without visible lesions 2
• Dysphagia or difficulty swallowing when pharyngeal branches are involved 2
• Odontalgia (tooth pain) as the only prodromal symptom, which can mislead clinicians 5

Diagnostic Approach

When to Suspect Zoster Sine Herpete

Consider this diagnosis when patients present with:

• Unilateral burning, stabbing, or aching pain in a dermatomal distribution without rash 6, 7
• Cranial nerve palsies (isolated or multiple) without cutaneous manifestations 2
• Immunocompromised status or advanced age with unexplained neurological symptoms 3

Laboratory Confirmation is Essential

PCR testing of cerebrospinal fluid or affected tissue is the gold standard for diagnosis when rash is absent 2. The American Geriatrics Society recommends confirmatory testing for atypical presentations, including Tzanck preparation, immunofluorescent viral antigen studies, culture, or PCR 6.

For oral involvement without rash:

• VZV DNA PCR from CSF shows high sensitivity when cranial nerves are affected 2
• Serum and CSF antibody titers can support the diagnosis 2
• Serology alone is not useful for acute diagnosis 7

Critical Differential Diagnosis

Herpes Simplex Virus Must Be Excluded

The Centers for Disease Control and Prevention emphasizes that HSV lesions progress through identical stages to VZV lesions (erythematous macules → papules → vesicles → pustules → ulcers), making clinical differentiation impossible without laboratory confirmation 8.

Key distinguishing features:

• HSV typically lacks the unilateral dermatomal distribution characteristic of zoster 8
• The 24-72 hour prodromal dermatomal pain is characteristic of zoster but not HSV 8
• Laboratory confirmation is essential in all cases of diagnostic uncertainty 8

Treatment Recommendations

Immediate Antiviral Therapy

The Infectious Diseases Society of America recommends initiating treatment immediately upon clinical suspicion without waiting for laboratory confirmation 7.

For immunocompetent patients:

• Oral valacyclovir or famciclovir are preferred over acyclovir due to superior bioavailability 7, 3
• Treatment should begin as soon as zoster sine herpete is suspected 7

For immunocompromised patients:

• High-dose intravenous acyclovir is the treatment of choice 6, 7
• These patients are at higher risk for atypical presentations and complications 3

Common Pitfalls to Avoid

Diagnostic Delays

• Do not dismiss unilateral oral pain without rash as non-viral in origin, especially in older or immunocompromised patients 2
• Lack of rash has been associated with delays in diagnosis and increased mortality in some cases 6
• Odontalgia as the sole presenting symptom can mislead dentists and delay proper diagnosis 5

Incomplete Evaluation

• Blood cultures have no role in diagnosing localized herpes zoster and should not delay antiviral therapy 6
• Skin biopsy is not indicated for typical presentations and is reserved for immunocompromised patients with atypical lesions 6

Risk Assessment

Screen for underlying immunosuppression when zoster sine herpete is diagnosed:

• HIV infection status 6
• Diabetes mellitus 6
• Active malignancy 6
• Immunosuppressive medications 6

These conditions increase both the risk and severity of atypical VZV presentations 6.