Practice Essentials
Varicella-zoster virus (VZV) causes chickenpox and herpes zoster (shingles). Chickenpox follows initial exposure to the virus and is typically a relatively mild, self-limited childhood illness with a characteristic exanthem, but can become disseminated in immunocompromised children. Reactivation of the dormant virus results in the characteristic painful dermatomal rash of herpes zoster, which is often followed by pain in the distribution of the rash (postherpetic neuralgia). See the image below.
Typical zoster in the vicinity of right popliteal fossa in a vertebral nerve L4 distribution.
Signs and symptoms
Pain and paresthesia are typically the first symptoms of VZV infection. Until the characteristic vesicular rash erupts, diagnosis may be difficult. A prodromal period during which symptoms may vary is common. Pain occurs in 41% of patients, itching in 27%, and paresthesias in 12%.
During the acute illness, patients may experience the following:
Pain (90%)
Helplessness and depression (20%)
Flulike symptoms (12%)
Herpes zoster (shingles)
The most common presentation is the shingles vesicular rash, which most commonly affects a thoracic dermatome
After a prodromal illness of pain and paresthesias, erythematous macules and papules develop and progress to vesicles within 24 hours
The vesicles eventually crust and resolve
Pain and sensory loss are the usual symptoms
Motor weakness also occurs and is frequently missed on examination
Cases of actual monoplegia due to VZV brachial plexus neuritis have been reported
Zoster multiplex
Shingles may appear in multiple dermatomes, both contiguous and noncontiguous, on either side of the body
Immunocompromised individuals are more susceptible
Terminology depends on the number of involved dermatomes and on whether the condition is unilateral or bilateral (eg, zoster duplex unilateralis refers to the involvement of 2 unilateral dermatomes)
Cases of zoster simultaneously occurring in 7 noncontiguous dermatomes have been reported
Zoster sine herpete
VZV infection may reactivate without causing cutaneous vesicles. These patients have severe dermatomal pain, possible motor weakness and possible hypesthesia, but no visible rash or vesicles.
VZV infection may present as acute peripheral facial palsy in 8-25% of patients who have no cutaneous vesicles. This is more common in immunosuppressed patients who use acyclovir (or other agents) as zoster prophylaxis.
Central nervous system deficits
More common in immunocompromised individuals, but do occur in the general population
CNS involvement may become apparent 3 weeks after the onset of the initial rash
The manifestations are usually bilateral
The physical findings may progress
The underlying pathology typically progresses for 3 or more weeks
Progression for 6 months in immunocompromised individuals has been reported
Recurrence is rare but has been reported
Zoster encephalitis is also rare but is reported in otherwise healthy individuals
Ramsay-Hunt syndrome
This syndrome occurs when the geniculate ganglion is involved. The clinical presentation includes the following:
A peripheral facial palsy
Pain in the ear and face
Vesicles in the external ear canal (not always present)
Additional auditory and vestibular symptoms in some cases
Keratitis (herpes ophthalmicus)
Caused by reactivation of VZV infection in the ophthalmic division of the trigeminal nerve.
The presentation may include conjunctivitis or corneal ulcers
Complications include blindness
Vesicles do not have to be present
Rarely, the virus migrates along the intracranial branches of the trigeminal nerve, causing thrombotic cerebrovasculopathy with severe headache and hemiplegia
See Clinical Presentation for more detail.
Diagnosis
When the presentation includes the typical dermatomal rash, additional studies are not required. Studies to consider in specific situations include the following:
If the diagnosis is in doubt, a Tzanck smear or culture of vesicular fluid can be performed
In cases of zoster sine herpete, DNA analysis via PCR can be used
In cases of acyclovir-resistant VZV, detections of mutations in thymidine kinase can be determined by PCR and sequence analysis
MRI may be useful if myelitis or encephalitis is suspected
Lumbar puncture may be helpful if signs suggest myelitis or encephalitis
See Workup for more detail.
Management
Treatment options are based on the following:
Patient age
Patient immune state
Duration of symptoms
Presentation
Antiviral medications decrease the duration of symptoms and the likelihood of postherpetic neuralgia, especially when initiated within 2 days of the onset of rash. Oral acyclovir may be prescribed in otherwise healthy patients who have typical cases. Compared with oral acyclovir, other medications (eg, valacyclovir, penciclovir, famciclovir) may decrease the duration of the patient’s pain.
Varicella zoster immune globulin (VariZIG) is indicated for administration to high-risk individuals within 10 days (ideally within 4 days) of chickenpox (VZV) exposure.
High- risk groups include the following:
Immunocompromised children and adults
Newborns of mothers with varicella shortly before or after delivery
Premature infants
Infants less than younger than 1 year of age
Adults without evidence of immunity
Pregnant women
See Treatment and Medication for more detail.