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Herpes zoster :

DESCRIPTION: | SIGNS AND SYMPTOMS: | CAUSES: | DIFFERENTIAL DIAGNOSIS: | LABORATORY: | PATHOLOGICAL FINDINGS: | IMAGING: | TREATMENT | DRUG(S) OF CHOICE | PRECAUTIONS: | ALTERNATIVE DRUGS: | PATIENT MONITORING: | POSSIBLE COMPLICATIONS: | MISCELLANEOUS

BASICS TOP

DESCRIPTION: TOP : A disease usually presenting as a painful unilateral dermatomal eruption. Zoster results from reactivation of varicella-zoster (chickenpox) virus that has been dormant in the dorsal root ganglia.

System(s) affected: Skin/Exocrine, Nervous

Genetics: N/A

Incidence/Prevalence in USA:

* 215/100,000/year; incidence is increasing as population ages

* Occurs in 10-20% of the population at some time

* Active herpes zoster 23.9/100,000

* Post herpetic neuralgia 86/100,000

Predominant age: Increasing incidence with aging. 80% of cases occur in persons over age 20 years (2-3 per 1000 age 20 to 50; 10 per 1000 > 80 years).

Predominant sex: Male = Female

SIGNS AND SYMPTOMS: TOP :

* Prodromal phase (sensations over involved dermatome prior to rash)

>> Tingling

>> Itching

>> Boring or knifelike pain

* Acute phase

>> Constitutional symptoms

>> Fatigue

>> Malaise

>> Headache

>> Low-grade fever

>> Dermatomal rash

>> Weakness (1% may have weakness in distribution of rash; herpes zoster motoricus)

>> Initially erythematous and maculopapular that evolves rapidly to grouped vesicles

>> Vesicles become pustular and/or hemorrhagic in 3 to 4 days

>> Resolution of rash with crusts separating by 14 to 21 days

>> Possible sine herpete (zoster without rash)

* Chronic phase

>> Postherpetic neuralgia (15% overall; increases dramatically with age)

>> A small percentage (1-5%) may affect the motor nerves causing weakness (herpes zoster motoricus), e.g., facial nerve (Ramsay Hunt syndrome), spinal motor radiculopathies

CAUSES: TOP Reactivation of dormant varicella-zoster (chicken pox) virus in dorsal root ganglia or gasserian ganglia

RISK FACTORS: TOP :

* Increasing age

* Compromised cell-mediated immunity in immunosuppressed patients or patients with malignancy (especially leukemia and lymphoma)

* Spinal surgery

* Spinal cord radiation

DIAGNOSIS

DIFFERENTIAL DIAGNOSIS: TOP :

* Rash - herpes simplex virus, Coxsackievirus, contact dermatitis, superficial pyoderma

* Pain - cholecystitis, pleuritis, myocardial infarction

LABORATORY: TOP :

* Rarely necessary

* Viral culture

* Tzanck smear (does not distinguish from herpes simplex and false negatives occur)

* Monoclonal antibody tests

* Blood mononuclear cell testing for viral DNA (research tool)

Drugs that may alter lab results: N/A

Disorders that may alter lab results: N/A

PATHOLOGICAL FINDINGS: TOP :

* Multinucleated giant cells with intralesional inclusion

* Lymphatic infiltration of sensory ganglia with focal hemorrhage and nerve cell destruction

SPECIAL TESTS: N/A

IMAGING: TOP : N/A

DIAGNOSTIC PROCEDURES: TOP : Biopsy for direct immunofluorescence testing (rarely done)

TREATMENT: TOP

APPROPRIATE HEALTH CARE: Outpatient unless disseminated or occurring as complication of serious underlying disease requiring hospitalization

GENERAL MEASURES: TOP :

* Wet dressings with tap water or 5% aluminum acetate (Burow's) applied 30 to 60 minutes 4-6 times per day

* Lotions such as calamine

SURGICAL MEASURES: N/A

ACTIVITY: No restrictions

DIET: No special diet

PATIENT EDUCATION:

* Duration of rash is 2-3 weeks

* Potential for dissemination and worrisome signs (constitutional illness signs and spreading rash)

* Potential postherpetic neuralgia

MEDICATIONS

DRUGS OF CHOICE: TOP :

* Antiviral agents, if initiated early (within 48 hours of rash) are of benefit in relieving symptoms and speeding resolution of rash. Postherpetic neuralgia is reduced when antiviral agents prescribed in acute phase of zoster. Clearly indicated for zoster associated with serious underlying condition and in ophthalmic zoster.

* Antiviral

>> Acyclovir (Zovirax) 800 mg every 4 hours (5 doses daily) for 7-10 days

>> Famciclovir 500-750 mg po tid for 7 days

>> Valacyclovir 1000 mg po tid for 7 days

* Pain medications (acetaminophen, codeine, nonsteroidal anti-inflammatory drugs)

* Silver sulfadiazine (Silvadene) topically for secondarily infected rash

Contraindications: Refer to manufacturer's profile of each drug

PRECAUTIONS: TOP :

* Monitor renal function when using acyclovir

* Acyclovir - pregnancy category C

* Refer to manufacturer's profile of each drug

Significant possible interactions:

* Acyclovir-probenecid: may inhibit excretion of acyclovir

ALTERNATIVE DRUGS: TOP :

* Vidarabine

* Topical idoxuridine in dimethyl sulfoxide (DMSO)

FOLLOWUP

PATIENT MONITORING: TOP : Symptom dependent

PREVENTION/AVOIDANCE:

* None at present

* Zoster patients may transmit virus causing varicella (chickenpox) to susceptible persons

* Varicella vaccines under investigation have not eliminated zoster

POSSIBLE COMPLICATIONS: TOP :

* Postherpetic neuralgia

* Ocular involvement with facial zoster

* Meningoencephalitis

* Cutaneous dissemination

* Superinfection of skin lesions

* Hepatitis

* Pneumonitis

* Peripheral motor weakness

* Segmental myelitis

* Cranial nerve syndromes especially ophthalmic and facial (Ramsay Hunt syndrome)

* Corneal ulceration

* Guillain-Barré syndrome

EXPECTED COURSE AND PROGNOSIS:

* Resolution of rash within 14 to 21 days

* Postherpetic neuralgia defined as pain persisting at least one month after rash has healed

* Postherpetic neuralgia incidence increases dramatically with age (4% age 30-50; 50% over age 80 years)

MISCELLANEOUS TOP

ASSOCIATED CONDITIONS: Immunocompromise including HIV infection, transplant recipients, and malignancies

AGE-RELATED FACTORS:

Pediatric:

* Occurs rarely in children (primarily immunosuppressed)

* Has been reported in infants primarily infected in utero

Geriatric:

* Increased incidence and prevalence

* Increased incidence of postherpetic neuralgia

Others: Consider HIV infection in young patients with zoster

PREGNANCY: Can occur during pregnancy

SYNONYMS: Shingles

ICD-9-CM: 053.9 (site specific codes not listed; preferred by Medicare)

IMAGES:

Herpes zoster

Herpes zoster

Herpes zoster

Herpes zoster

Herpes zoster

Post-zoster scarring

Herpes zoster

Herpes zoster

SEE ALSO:

* Chickenpox

* Herpes simplex

* Herpes eye infections

* Bell's palsy

OTHER NOTES: Corticosteroid efficacy to prevent postherpetic neuralgia remains controversial. Capsaicin, transcutaneous electrical nerve stimulation (TENS) and low dose amitriptyline are the current treatment(s) of choice for postherpetic neuralgia.

ABBREVIATIONS: N/A

REFERENCES:

* Martin JW, et al: A randomized trial of acyclovir for 7 days or 21 days with and without prednisolone for treatment of acute herpes zoster. NEJM 1993;30:896-900

* Donahue JG, et al: The Incidence of Herpes Zoster. Arch Intern Med 1995;155:1605

* Tyring S, et al: Famciclovir for the Treatment of Acute Herpes Zoster: Effects on Acute Disease and Postherpetic Neuralgia. Annals of Internal Medicine 1995;123:89

Author(s):

Larry W. Halverson, MD

Copyright - Williams & Wilkins, 1997.

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