Herpes Zoster from Emergency Medicine / Infectious Diseases

eMedicine Journal > Emergency Medicine > Infectious Diseases Herpes Zoster Synonyms, Key Words, and Related Terms: shingles, zona ignea, zona serpiginosa, zoster, herpesvirus, varicella-zoster virus, varicella-zoster virus infection, zoster sine herpete, chickenpox, vesicular rash, zoster keratitis, Ramsay Hunt syndrome, herpes zoster oticus, transitory unilateral facial paralysis, postherpetic neuralgia, conjunctivitis, keratitis, corneal ulceration, iridocyclitis, glaucoma, peripheral facialnerve weakness, peripheral facial nerve palsy, myelitis, cranial nerve palsies, granulomatous angiitis, disseminated zoster, encephalitis, hepatitis, pneumonitis, tingling, burning, trigeminal neuralgia, herniated nucleus pulposus with radiculopathy, erythematous rash, meningoencephalitis
Author Information \| Introduction \| Clinical \| Differentials \| Workup \| Treatment \| Medication \| Follow-up \| Miscellaneous \| Test Questions \| Pictures \| Bibliography

AUTHOR INFORMATION Section 1 of 12

Authored by Chris D Melton, MD, Assistant Professor, Department of Emergency Medicine, University of Arkansas for Medical Sciences

Chris D Melton, MD, is a member of the following medical societies: Arkansas Medical Society

Edited by Jeffrey Glenn Bowman, MD, MS, Consulting Staff, Department of Emergency Medicine, Mercy Springfield Hospital; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Eric L Weiss, MD, DTM&H, Director of Stanford Travel Medicine, Medical Director of Stanford Lifeflight, Assistant Professor, Departments of Emergency Medicine and Infectious Diseases, Stanford University School of Medicine; John Halamka, MD, Chief Information Officer, CareGroup Healthcare System, Assistant Professor of Medicine, Department of Emergency Medicine, Beth Israel Deaconess Medical Center; Assistant Professor of Medicine, Harvard Medical School; and Steven C Dronen, MD, FAAEM, Director of Emergency Services, Director of Chest Pain Center, Department of Emergency Medicine, Ft Sanders Sevier Medical Center

Author's Email: Chris D Melton, MD
Editor's Email: Jeffrey Glenn Bowman, MD, MS

Author's Email:	Chris D Melton, MD
Editor's Email:	Jeffrey Glenn Bowman, MD, MS

eMedicine Journal, July 12 2006, VOLUME 7, Number 7

INTRODUCTION Section 2 of 12

Background: Varicella-zoster virus infection initially produces chickenpox. Following resolution of the chickenpox, the virus lies dormant in the dorsal root ganglia until focal reactivation along a ganglion's distribution results in herpes zoster (shingles).

Although the exact precipitants that result in viral reactivation are not known certainly, decreased cellular immunity appears to increase the risk of reactivation.

Pathophysiology: Herpes zoster manifests as a vesicular rash, usually in a single dermatome. Development of the rash may be preceded by paresthesias or pain along the involved dermatome. Ocular involvement and zoster keratitis may result if reactivation occurs along the ophthalmic division of the trigeminal nerve.

Involvement of the geniculate ganglion may produce the syndrome of Ramsay Hunt. Ramsay Hunt syndrome is characterized by development of pain in the ear and usually transitory unilateral facial paralysis with herpetic vesicles of the external ear or tympanic membrane (without paralysis, this is termed Herpes Zoster Oticus). Occasionally, Ramsay Hunt syndrome is associated with vertigo, tinnitus, and hearing disorders.

Frequency:

In the US: Approximately 95% of adults in the United States have antibodies to the varicella-zoster virus. Herpes zoster occurs annually in 300,000-500,000 individuals.

Mortality/Morbidity:

A common complication following herpes zoster is postherpetic neuralgia. Postherpetic neuralgia is characterized by pain that persists for longer than 1 month following resolution of the vesicular rash. This complication is more common in patients older than 50 years. Postherpetic neuralgia may develop as a continuation of pain that accompanies acute zoster or it may develop following apparent resolution of the initial zoster reactivation. The pain of postherpetic neuralgia usually resolves within 6 months. However, 1% of patients continue to have pain for 1 year or longer.
Herpes zoster may be associated with a secondary bacterial infection (typically streptococcal or staphylococcal) of the vesicular rash.

Herpes zoster involving the second branch of the trigeminal nerve may be associated with conjunctivitis, keratitis, corneal ulceration, iridocyclitis, glaucoma, and blindness.
Complications of the Ramsay Hunt syndrome may include peripheral facial nerve weakness and deafness.
Meningoencephalitis secondary to herpes zoster is more likely to be seen in immunocompromised patients than in immunocompetent patients. Other CNS complications may include myelitis, cranial nerve palsies, and granulomatous angiitis. Granulomatous angiitis may result in the development of a cerebrovascular accident.

Disseminated zoster may be seen in immunocompromised patients. In such cases, hematogenous spread may result in the involvement of multiple dermatomes. Visceral involvement also can occur. Such systemic involvement can lead to death due to encephalitis, hepatitis, or pneumonitis.

Race: Among those patients who have had exposure to chickenpox, blacks are 25% less likely than whites to develop herpes zoster.

Sex: Incidence is equal in males and females.

Age: Incidence of herpes zoster increases with age. Approximately 80% of cases occur in persons older than 20 years.
CLINICAL Section 3 of 12

History:

Most patients who develop zoster have a 2-3 day prodrome of pain, tingling, or burning in the involved dermatome.

Misdiagnosis is most likely to occur during this time.

During this prodromal period, patients may present with symptoms consistent with acute myocardial infarction, urolithiasis, pleurisy, trigeminal neuralgia, appendicitis, cholelithiasis, or herniated nucleus pulposus with radiculopathy, depending upon the involved dermatome.

The most commonly involved dermatomes are those of the thorax.

Acute phase includes the following:

Constitutional symptoms

Fatigue

Malaise

Headache

Low-grade fever

Vesicular rash in the involved dermatome
- Progression of the rash to pustules over a period of several days
- Crusting of lesions before the rash resolves

Pain may or may not subside.

Pain lasting longer than 1 month is referred to, by definition, as postherpetic neuralgia.

Zoster sine herpete is defined as pain and paresthesias along the dermatome without the development of visible cutaneous involvement.

Physical:

The primary physical finding is a rash in a unilateral dermatomal distribution; the rash may be erythematous, vesicular, pustular, or crusting, depending on the stage of disease (see Images 1-2).

Bilateral rash is rare.

Zoster lesions occur simultaneously and remain in congruent stages of healing.

Lesions on the tip of the nose signify involvement of the nasociliary nerve; this finding mandates slit-lamp examination with fluorescein stain to look for the dendritic corneal lesions of herpetic keratitis.

Depending on the dermatome involved, physical exam findings may include the following:

Corneal ulcers, conjunctivitis

Regional lymphadenopathy

Cranial nerve palsies

Peripheral facial nerve palsy

Delirium, confusion, coma (in patients with meningoencephalitis)

Causes: The exact mechanism of varicella-zoster reactivation is not known; however, decreased cellular immunity is a causative factor.
DIFFERENTIALS Section 4 of 12

Appendicitis, Acute
Bell Palsy
Cholecystitis and Biliary Colic
Conjunctivitis
Corneal Ulceration and Ulcerative Keratitis
Glaucoma, Acute Angle-Closure
Herpes Simplex
Herpes Zoster
Herpes Zoster Ophthalmicus
Herpes Zoster Oticus
Renal Calculi
Trigeminal Neuralgia

Other Problems to be Considered:

Coxsackievirus
Superficial pyoderma

WORKUP Section 5 of 12

Lab Studies:

In the ED, diagnosis of herpes zoster is based primarily on clinical findings. However, in some patients, the presentation of herpes zoster can be atypical and may require additional testing. This is particularly true in immunocompromised patients.

Varicella-zoster virus can be cultured successfully; however, this method is not practical for use in the ED because of the virus's slow growth.

Tzanck smear can be obtained from the vesicular lesions; however, the smear does not differentiate between varicella-zoster virus infections such as herpes zoster and herpes simplex.

Direct immunofluorescence assay may be performed to detect varicella-zoster and can distinguish varicella-zoster from herpes simplex.

Other Tests:

Monoclonal antibody tests

Blood mononuclear cell testing for viral DNA (research)

Procedures:

Biopsy for direct immunofluorescence testing (rarely performed)

TREATMENT

Section 6 of 12

Emergency Department Care:

Patients with herpes zoster usually experience severe pain.

Initial therapy may include nonsteroidal anti-inflammatory drugs (NSAIDs).

In many cases, narcotic analgesia is necessary.

Wet dressings with tap water or 5% aluminum acetate (Burow solution) and apply to affected skin for 30-60 minutes 4-6 times per day.

Lotions (ie, Calamine) may help relieve discomfort.

MEDICATION

Section 7 of 12

Goals of therapy in herpes zoster infection are to (1) shorten the clinical course, (2) provide analgesia, (3) prevent complications, and (4) decrease incidence of postherpetic neuralgia.

Drug Category: Antiviral agents -- Acyclovir antivirals may decrease incidence of postherpetic neuralgia. Famciclovir and valacyclovir (2 antiviral agents with properties similar to those of acyclovir) offer better dosing regimens than acyclovir and yet are less studied.

Drug Name
Acyclovir (Zovirax) -- Reduces duration of symptomatic lesions. Indicated for patients presenting within 48 h of onset of rash. Treated patients experience less pain and faster resolution of cutaneous lesions.
Adult Dose Immunocompromised adults: 800 mg PO q4h (5 times/d) for 7-10 d; alternatively, 10 mg/kg/dose or 500 mg/m²/dose IV q8h
Pediatric Dose Immunocompromised children: 250-600 mg/m²/dose PO 4-5 times/d for 7-10 d; alternatively, 10 mg/kg/dose or 500 mg/m²/dose IV q8h
Contraindications Documented hypersensitivity
Interactions Probenecid or zidovudine prolongs half-life and increases CNS toxicity
Pregnancy B - Usually safe but benefits must outweigh the risks.
Precautions Caution with renal failure or coadministration of other nephrotoxic drugs
Drug Name
Famciclovir (Famvir) -- Prodrug that, when biotransformed into active metabolite penciclovir, may inhibit viral DNA synthesis/replication.
Adult Dose 500 mg PO q8h for 7 d
Pediatric Dose Not established
Contraindications Documented hypersensitivity
Interactions Probenecid or cimetidine may increase toxicity; increases bioavailability of digoxin
Pregnancy B - Usually safe but benefits must outweigh the risks.
Precautions Caution in renal failure or coadministration of nephrotoxic drugs
Drug Name
Valacyclovir (Valtrex) -- Prodrug rapidly converted to acyclovir before exerting its antiviral activity. More expensive but more convenient dosing regimen than acyclovir.
Adult Dose 1000 mg PO q8h for 7 d
Pediatric Dose Not established
Contraindications Documented hypersensitivity
Interactions Probenecid, zidovudine, or cimetidine prolongs half-life and increases CNS toxicity
Pregnancy B - Usually safe but benefits must outweigh the risks.
Precautions Caution in renal failure and coadministration of nephrotoxic drugs; associated with onset of hemolytic uremic syndrome
Drug Category: Corticosteroids -- These agents have anti-inflammatory properties and cause profound and varied metabolic effects. Corticosteroids modify the body's immune response to diverse stimuli.
Drug Name
Prednisone (Deltasone, Orasone, Meticorten) -- The addition of a corticosteroid to acyclovir resulted in decreased acute pain but no decrease in long-term pain. One study also demonstrated more rapid initial healing of rash, although time to complete rash resolution was unchanged.
Adult Dose 60 mg/d PO tapered over 3 wk
Pediatric Dose 0.05-2 mg/kg PO divided bid/qid; taper over 2 wk
Contraindications Documented hypersensitivity; viral, fungal, tubercular skin, and connective tissue infections; peptic ulcer disease; hepatic dysfunction; GI bleeding or ulceration
Interactions Coadministration with estrogens may decrease clearance; concurrent use with digoxin may cause digitalis toxicity secondary to hypokalemia; phenobarbital, phenytoin, and rifampin may increase metabolism of glucocorticoids (consider increasing maintenance dose); monitor for hypokalemia with coadministration of diuretics
Pregnancy B - Usually safe but benefits must outweigh the risks.
Precautions Abrupt discontinuation of glucocorticoids may cause adrenal crisis; hyperglycemia, edema, osteonecrosis, myopathy, peptic ulcer disease, hypokalemia, osteoporosis, euphoria, psychosis, myasthenia gravis, growth suppression, and infections may occur with glucocorticoid use
Drug Category: Analgesics -- Pain control is essential to quality patient care. Analgesics ensure patient comfort, promote pulmonary toilet, and enable physical therapy regimens. Most analgesics have sedating properties that are beneficial for patients who have skin lesions.
Drug Name
Acetaminophen (Tylenol, Aspirin-Free Anacin) -- DOC for treatment of pain in patients who (1) have documented hypersensitivity to aspirin or NSAIDs; (2) have upper GI disease; or (3) are taking oral anticoagulants. Reduces fever by direct action on hypothalamic heat-regulating centers, which increases dissipation of body heat via vasodilation and sweating.
Adult Dose 325-650 mg PO q6h, or 1000 mg tid/qid; not to exceed 4 g/d
Pediatric Dose <12 years: 10-15 mg/kg/dose PO q4-6h prn; not to exceed 2.6 g/d
>12 years: 650 mg q4h; not to exceed 5 doses in 24 h
Contraindications Documented hypersensitivity; known G-6-P deficiency
Interactions Rifampin can reduce analgesic effects; barbiturates, carbamazepine, hydantoins, and isoniazid may increase hepatotoxicity
Pregnancy B - Usually safe but benefits must outweigh the risks.
Precautions Hepatotoxicity possible in chronic alcoholics following various dose levels; severe or recurrent pain or high or continued fever may indicate serious illness; APAP contained in many OTC products, and combined use with these products may result in cumulative APAP doses exceeding recommended maximum dose
Drug Name
Ibuprofen (Motrin, Advil, Nuprin) -- DOC for treatment of mild to moderately severe pain, if no contraindications. Inhibits inflammatory reactions and pain, probably by decreasing activity of enzyme cyclooxygenase, in turn inhibiting prostaglandin synthesis. One of few NSAIDs indicated for reduction of fever.
Adult Dose 200-400 mg PO q4-6h while symptoms persist; not to exceed 3.2 g/d
Pediatric Dose <16 years: Not recommended because of association with Reye syndrome
>16 years: Administer as in adults
Contraindications Documented hypersensitivity; peptic ulcer disease; recent GI bleeding or perforation; renal insufficiency; high risk of bleeding
Interactions Aspirin increases risk of inducing serious NSAID-related adverse effects; probenecid may increase concentrations and, possibly, toxicity; may decrease effects of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; may increase PT in patients taking anticoagulants�monitor PT closely and instruct patients to watch for signs of bleeding; may increase risk of methotrexate toxicity; may increase phenytoin levels
Pregnancy B - Usually safe but benefits must outweigh the risks.
Precautions Category D in third trimester of pregnancy; caution in congestive heart failure, hypertension, and decreased renal and hepatic function; caution in coagulation abnormalities or during anticoagulant therapy
Drug Category: Vaccines -- Elicit active immunization to increase resistance to infection. Vaccines consist of attenuated microorganisms or cellular components, which act as antigens. Administration stimulates antibody production with specific protective properties.
Drug Name
Varicella zoster vaccine (Zostavax) -- Lyophilized preparation of Oka/Merck strain of live, attenuated varicella-zoster virus (VZV). Shown to boost immunity against herpes zoster virus (shingles) in older patients. Reduces occurrence of shingles in individuals >60 y by about 50%. For individuals aged 60-69 y, it reduces occurrence by 64%. Also slightly reduces pain compared with no vaccination in those who develop shingles. Indicated for prevention of herpes zoster.
Adult Dose <60 years: Not established
>60 years: Following reconstitution with entire vial of diluent supplied, use separate sterile needle and syringe to withdraw entire contents of reconstituted vial and administer SC; administer in upper arm
Pediatric Dose Not indicated
Contraindications Documented hypersensitivity to vaccine or components (eg, gelatin, neomycin); history of primary or acquired immunodeficiency states (eg, leukemia, lymphomas, malignant neoplasms affecting bone marrow or lymphatic system, AIDS); immunosuppressive therapy including high-dose corticosteroids; active, untreated tuberculosis
Interactions None reported
Pregnancy C - Safety for use during pregnancy has not been established.
Precautions Common adverse effects include erythema, pain, tenderness, itching, and inflammation at injection site; may also cause headache; may cause extensive vaccine-associated rash or disseminated disease in individuals on immunosuppressive therapy (see Contraindications); defer vaccination if fever or acute illness present; do not inject intravascularly; administer within 30 min of reconstitution; not a substitute for varicella virus vaccine (Varivax) for children
FOLLOW-UP Section 8 of 12

Drug Name	Acyclovir (Zovirax) -- Reduces duration of symptomatic lesions. Indicated for patients presenting within 48 h of onset of rash. Treated patients experience less pain and faster resolution of cutaneous lesions.
Adult Dose	Immunocompromised adults: 800 mg PO q4h (5 times/d) for 7-10 d; alternatively, 10 mg/kg/dose or 500 mg/m²/dose IV q8h
Pediatric Dose	Immunocompromised children: 250-600 mg/m²/dose PO 4-5 times/d for 7-10 d; alternatively, 10 mg/kg/dose or 500 mg/m²/dose IV q8h
Contraindications	Documented hypersensitivity
Interactions	Probenecid or zidovudine prolongs half-life and increases CNS toxicity
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Caution with renal failure or coadministration of other nephrotoxic drugs

Drug Name	Famciclovir (Famvir) -- Prodrug that, when biotransformed into active metabolite penciclovir, may inhibit viral DNA synthesis/replication.
Adult Dose	500 mg PO q8h for 7 d
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity
Interactions	Probenecid or cimetidine may increase toxicity; increases bioavailability of digoxin
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Caution in renal failure or coadministration of nephrotoxic drugs

Drug Name	Valacyclovir (Valtrex) -- Prodrug rapidly converted to acyclovir before exerting its antiviral activity. More expensive but more convenient dosing regimen than acyclovir.
Adult Dose	1000 mg PO q8h for 7 d
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity
Interactions	Probenecid, zidovudine, or cimetidine prolongs half-life and increases CNS toxicity
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Caution in renal failure and coadministration of nephrotoxic drugs; associated with onset of hemolytic uremic syndrome

Drug Name	Prednisone (Deltasone, Orasone, Meticorten) -- The addition of a corticosteroid to acyclovir resulted in decreased acute pain but no decrease in long-term pain. One study also demonstrated more rapid initial healing of rash, although time to complete rash resolution was unchanged.
Adult Dose	60 mg/d PO tapered over 3 wk
Pediatric Dose	0.05-2 mg/kg PO divided bid/qid; taper over 2 wk
Contraindications	Documented hypersensitivity; viral, fungal, tubercular skin, and connective tissue infections; peptic ulcer disease; hepatic dysfunction; GI bleeding or ulceration
Interactions	Coadministration with estrogens may decrease clearance; concurrent use with digoxin may cause digitalis toxicity secondary to hypokalemia; phenobarbital, phenytoin, and rifampin may increase metabolism of glucocorticoids (consider increasing maintenance dose); monitor for hypokalemia with coadministration of diuretics
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Abrupt discontinuation of glucocorticoids may cause adrenal crisis; hyperglycemia, edema, osteonecrosis, myopathy, peptic ulcer disease, hypokalemia, osteoporosis, euphoria, psychosis, myasthenia gravis, growth suppression, and infections may occur with glucocorticoid use

Drug Name	Acetaminophen (Tylenol, Aspirin-Free Anacin) -- DOC for treatment of pain in patients who (1) have documented hypersensitivity to aspirin or NSAIDs; (2) have upper GI disease; or (3) are taking oral anticoagulants. Reduces fever by direct action on hypothalamic heat-regulating centers, which increases dissipation of body heat via vasodilation and sweating.
Adult Dose	325-650 mg PO q6h, or 1000 mg tid/qid; not to exceed 4 g/d
Pediatric Dose	<12 years: 10-15 mg/kg/dose PO q4-6h prn; not to exceed 2.6 g/d >12 years: 650 mg q4h; not to exceed 5 doses in 24 h
Contraindications	Documented hypersensitivity; known G-6-P deficiency
Interactions	Rifampin can reduce analgesic effects; barbiturates, carbamazepine, hydantoins, and isoniazid may increase hepatotoxicity
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Hepatotoxicity possible in chronic alcoholics following various dose levels; severe or recurrent pain or high or continued fever may indicate serious illness; APAP contained in many OTC products, and combined use with these products may result in cumulative APAP doses exceeding recommended maximum dose

Drug Name	Ibuprofen (Motrin, Advil, Nuprin) -- DOC for treatment of mild to moderately severe pain, if no contraindications. Inhibits inflammatory reactions and pain, probably by decreasing activity of enzyme cyclooxygenase, in turn inhibiting prostaglandin synthesis. One of few NSAIDs indicated for reduction of fever.
Adult Dose	200-400 mg PO q4-6h while symptoms persist; not to exceed 3.2 g/d
Pediatric Dose	<16 years: Not recommended because of association with Reye syndrome >16 years: Administer as in adults
Contraindications	Documented hypersensitivity; peptic ulcer disease; recent GI bleeding or perforation; renal insufficiency; high risk of bleeding
Interactions	Aspirin increases risk of inducing serious NSAID-related adverse effects; probenecid may increase concentrations and, possibly, toxicity; may decrease effects of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; may increase PT in patients taking anticoagulants�monitor PT closely and instruct patients to watch for signs of bleeding; may increase risk of methotrexate toxicity; may increase phenytoin levels
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Category D in third trimester of pregnancy; caution in congestive heart failure, hypertension, and decreased renal and hepatic function; caution in coagulation abnormalities or during anticoagulant therapy

Drug Name	Varicella zoster vaccine (Zostavax) -- Lyophilized preparation of Oka/Merck strain of live, attenuated varicella-zoster virus (VZV). Shown to boost immunity against herpes zoster virus (shingles) in older patients. Reduces occurrence of shingles in individuals >60 y by about 50%. For individuals aged 60-69 y, it reduces occurrence by 64%. Also slightly reduces pain compared with no vaccination in those who develop shingles. Indicated for prevention of herpes zoster.
Adult Dose	<60 years: Not established >60 years: Following reconstitution with entire vial of diluent supplied, use separate sterile needle and syringe to withdraw entire contents of reconstituted vial and administer SC; administer in upper arm
Pediatric Dose	Not indicated
Contraindications	Documented hypersensitivity to vaccine or components (eg, gelatin, neomycin); history of primary or acquired immunodeficiency states (eg, leukemia, lymphomas, malignant neoplasms affecting bone marrow or lymphatic system, AIDS); immunosuppressive therapy including high-dose corticosteroids; active, untreated tuberculosis
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Common adverse effects include erythema, pain, tenderness, itching, and inflammation at injection site; may also cause headache; may cause extensive vaccine-associated rash or disseminated disease in individuals on immunosuppressive therapy (see Contraindications); defer vaccination if fever or acute illness present; do not inject intravascularly; administer within 30 min of reconstitution; not a substitute for varicella virus vaccine (Varivax) for children

Deterrence/Prevention:

Theoretically, current varicella vaccines will reduce zoster incidence.

Vaccines are being tested for prevention of herpes zoster in individuals previously infected with wild varicella-zoster virus.

Patients with zoster may transmit the virus, causing varicella (chickenpox) to susceptible persons.

Complications:

Postherpetic neuralgia

Ocular involvement with facial zoster

Meningoencephalitis

Cutaneous dissemination

Superinfection of skin lesions

Hepatitis/pneumonitis

Peripheral motor weakness/segmental myelitis

Cranial nerve syndromes, particularly ophthalmic and facial (Ramsay Hunt syndrome)

Corneal ulceration

Guillain-Barr� syndrome

Prognosis:

Rash usually resolves within 14-21 days.

Postherpetic neuralgia is defined as pain persisting at least 1 month after the rash has healed. Its incidence increases dramatically with age (ie, 4% in those aged 30-50 years, 50% in those older than 80 years).

Patient Education:

For excellent patient education resources, visit eMedicine's Bacterial and Viral Infections Center. Also, see eMedicine's patient education articles Shingles and Chickenpox.

MISCELLANEOUS

Section 9 of 12

Medical/Legal Pitfalls:

Failure to recognize involvement of the nasociliary nerve as demonstrated by lesions on the tip of the nose; therefore, failure to perform a slit-lamp exam with fluorescein stain to identify the dendritic corneal lesions of herpetic keratitis

Failure to provide optimal analgesia, thereby allowing pain and suffering (eg, using NSAIDs when a narcotic analgesic combination is indicated)

Failure to administer antiviral therapy to those who are immunocompromised

TEST QUESTIONS

Section 10 of 12

CME Question 1: Which of the following statements regarding herpes zoster is false?

A: Antiviral therapy is most effective if given within the first 48 hours.
B: Vesicular lesions of herpes zoster are infectious.
C: Incidence of herpes zoster decreases in patients older than 50 years.
D: Acyclovir is the active metabolite of valacyclovir.
E: Herpes zoster occurs less frequently in blacks than whites.

The correct answer is C: Incidence of herpes zoster increases with age, as does the risk of postherpetic neuralgia.

CME Question 2: What is the most common dermatomal region for reactivation of the varicella-zoster virus?

A: Cervical
B: Thoracic
C: Lumbar
D: Sacral
E: Thoracolumbar

The correct answer is B: The rash may, however, occur on any part of the body. It is usually confined to a single dermatome in immunocompetent patients. Bilateral rash is rare.

Pearl Question 1 (T/F): Postherpetic neuralgia and secondary infection are the 2 most common complications of herpes zoster.

The correct answer is True: Postherpetic neuralgia usually resolves within 6 months. However, a small percentage of patients continue to have pain for longer than 1 year. Another common complication is secondary infection with staphylococcal or streptococcal pathogens.

Pearl Question 2 (T/F): Urolithiasis has symptoms similar to those seen in the prodromal period of herpes zoster.

The correct answer is True: Urolithiasis, abdominal aortic aneurysm, myocardial infarction, appendicitis, pleurisy, trigeminal neuralgia, herniated nucleus pulposus, and cholelithiasis all may be mistaken for the prodromal phase of herpes zoster.

Pearl Question 3 (T/F): Reactivation of herpes zoster can occur without visible cutaneous involvement.

The correct answer is True: Zoster cine herpete manifests as pain, abnormal sensation, and burning in a dermatomal distribution without the development of rash.

Pearl Question 4 (T/F): Pain must last longer than 1 month after resolution of the vesicular rash to qualify for the diagnosis of postherpetic neuralgia.

The correct answer is True: Postherpetic neuralgia by definition requires that pain last longer than 1 month. The pain typically lasts no longer than 6 months.
PICTURES Section 11 of 12

Caption: Picture 1. Herpes zoster on the neck.
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Caption: Picture 2. Herpes zoster on the lateral part of the abdomen.
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BIBLIOGRAPHY Section 12 of 12

Brody MB, Moyer D: Varicella-zoster virus infection. The complex prevention-treatment picture. Postgrad Med 1997 Jul; 102(1): 187-90, 192-4[Medline].
Kost RG, Straus SE: Postherpetic neuralgia--pathogenesis, treatment, and prevention. N Engl J Med 1996 Jul 4; 335(1): 32-42[Medline].
Nikkels AF, Pierard GE: Recognition and treatment of shingles. Drugs 1994 Oct; 48(4): 528-48[Medline].
Straus SE: Overview: the biology of varicella-zoster virus infection. Ann Neurol 1994; 35 Suppl: S4-8[Medline].
Whitley RJ, Weiss H, Gnann JW, et al: Acyclovir with and without prednisone for the treatment of herpes zoster. A randomized, placebo-controlled trial. The National Institute of Allergy and Infectious Diseases Collaborative Antiviral Study Group. Ann Intern Med 1996 Sep 1; 125(5): 376-83[Medline].
Wood MJ: Current experience with antiviral therapy for acute herpes zoster. Ann Neurol 1994; 35 Suppl: S65-8[Medline].
Wood MJ, Johnson RW, McKendrick MW, et al: A randomized trial of acyclovir for 7 days or 21 days with and without prednisolone for treatment of acute herpes zoster. N Engl J Med 1994 Mar 31; 330(13): 896-900[Medline].

NOTE:
Medicine is a constantly changing science and not all therapies are clearly established. New research changes drug and treatment therapies daily. The authors, editors, and publisher of this journal have used their best efforts to provide information that is up-to-date and accurate and is generally accepted within medical standards at the time of publication. However, as medical science is constantly changing and human error is always possible, the authors, editors, and publisher or any other party involved with the publication of this article do not warrant the information in this article is accurate or complete, nor are they responsible for omissions or errors in the article or for the results of using this information. The reader should confirm the information in this article from other sources prior to use. In particular, all drug doses, indications, and contraindications should be confirmed in the package insert. FULL DISCLAIMER

NOTE:

Medicine is a constantly changing science and not all therapies are clearly established. New research changes drug and treatment therapies daily. The authors, editors, and publisher of this journal have used their best efforts to provide information that is up-to-date and accurate and is generally accepted within medical standards at the time of publication. However, as medical science is constantly changing and human error is always possible, the authors, editors, and publisher or any other party involved with the publication of this article do not warrant the information in this article is accurate or complete, nor are they responsible for omissions or errors in the article or for the results of using this information. The reader should confirm the information in this article from other sources prior to use. In particular, all drug doses, indications, and contraindications should be confirmed in the package insert. FULL DISCLAIMER

Caption: Picture 1. Herpes zoster on the neck.
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Caption: Picture 2. Herpes zoster on the lateral part of the abdomen.
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Picture Type: Photo