Can Shingles Occur Without a Rash?
Yes, shingles can occur without a visible rash, a condition known as "zoster sine herpete" (zoster without rash), though this presentation is uncommon and requires a high index of suspicion for diagnosis. 1, 2
Clinical Evidence for Rash-Free Shingles
Varicella-zoster virus (VZV) reactivation can produce radicular pain without the characteristic zosteriform rash, and virologic evidence confirms these cases represent true VZV reactivation rather than alternative diagnoses 2
VZV can produce neurologic and visceral diseases in the complete absence of both rash and radicular pain, expanding the clinical spectrum beyond the classic dermatomal presentation 2
VZV DNA has been detected in blood mononuclear cells of elderly individuals without any skin lesions, neurologic symptoms, or systemic disease manifestations, providing molecular evidence for subclinical reactivation 2
Atypical Presentations That May Lack Rash
Patients may present with nonspecific lesions that do not initially have the vesicular appearance of typical zoster, and the rash might be atypical, localized, faint, or evanescent in some cases 1
In individuals with darker skin pigmentation, the rash might be difficult to recognize even when present, potentially leading to misclassification as "no rash" 1
Painless herpes zoster has been documented in elderly patients, demonstrating that both the pain and rash components can be absent or minimal 3
Diagnostic Approach When Rash Is Absent
When zoster sine herpete is suspected based on dermatomal pain without visible rash, diagnostic testing becomes essential rather than optional:
Tzanck smear showing giant cells can confirm herpesvirus infection but cannot distinguish between HSV and VZV 1
Vesicle fluid specimens (when any lesions are present) can be obtained for immunofluorescence antigen testing, culture, or PCR to confirm diagnosis 1
Laboratory confirmation is particularly needed for immunocompromised patients with atypical clinical presentations 1
Consider PCR testing of blood or cerebrospinal fluid when neurologic symptoms are present without rash 2
Clinical Implications and Management
Even without visible rash, antiviral treatment should be initiated when zoster sine herpete is suspected based on characteristic dermatomal pain:
Oral antiviral therapy with acyclovir, valacyclovir, or famciclovir should be initiated as soon as possible after diagnosis to reduce viral replication and prevent complications 1
High-dose IV acyclovir is recommended for immunocompromised hosts, even in the absence of rash 1
Lack of rash or late-onset rash in herpes zoster has been associated with delays in diagnosis and increased mortality in some cases, making early recognition critical 1
Key Clinical Pitfalls
The absence of rash does not exclude VZV reactivation, and relying solely on visible skin findings will miss zoster sine herpete cases 2
Prodromal dermatomal pain that precedes skin findings by 24-72 hours is characteristic of zoster, and patients presenting during this window may not yet have developed the rash 1
Alternative diagnoses that may mimic herpes zoster should be considered, especially in the absence of characteristic pain, but VZV reactivation should remain in the differential 1
Immunocompromised patients may develop chronic ulcerations with persistent viral replication, and secondary bacterial and fungal superinfections can occur, complicating the clinical picture even further 1