TREATMENT
Treatment of HZ infection is focused on limiting the extent, duration, and severity of pain and rash in the primary dermatome, as well as decreasing the risk for complications.
Topical Therapy
Patients should keep the cutaneous lesions clean and dry to reduce the risk for bacterial superinfection. A sterile, nonocclusive, nonadherent dressing placed over the involved dermatome will protect the lesions from contact with clothing. To hasten the drying of vesicular lesions and alleviate pruritus associated with rash, the application of cool compresses, calamine lotion, cornstarch, or baking soda may be helpful.16,21
While antipruritic agents may help prevent infections that can develop when the affected area is scratched, there is no evidence that any of these agents have any real therapeutic effect on the HZ rash or lesions. Topical antiviral agents are not effective.15,18
Antiviral Therapy
Treatment for acute HZ with oral antiviral medication should be considered for any patient who presents within 72 hours of rash onset; antiviral agents initiated within this time frame have been shown to reduce the duration and severity of pain associated with acute HZ.21 Antivirals are recommended and should be given routinely to patients older than 50 and those who have moderate to severe symptoms.15,21
Among patients who present longer than 72 hours after rash onset, antiviral therapy should be considered only for those with new vesicular formation, ophthalmic involvement, or motor or neurologic complications, although evidence is lacking for this recommendation.15,21 A modest reduction in the duration of rash (by 1 to 3 days) has also been reported in patients treated with antivirals,21 most likely because viral replication is slowed within the dorsal root ganglion.16,22
Acyclovir, valacyclovir, and famciclovir—nucleoside analogs that block viral replication—are the only FDA-approved medications for treatment of HZ.18,22 When choosing among these agents, the prescribing clinician should be aware of their differences in bioavailability and pharmacokinetics. Acyclovir, for example, is a second-generation antiviral drug with poor pharmacokinetics, which explains the frequent dosing its use generally requires.22,23 However, the inhibitory dose of acyclovir required for patients with HZ is much lower than that required to treat primary VZV infection.
Valacyclovir and famciclovir, which are third-generation antivirals, feature enhanced absorption from the gastrointestinal tract (77% vs 30% for acyclovir),24 thus improving their bioavailability by three to five times, compared with acyclovir. The superior pharmacokinetics of valacyclovir and famciclovir has been confirmed clinically by researchers who demonstrated median pain duration of 38 days in patients taking valacyclovir, compared with 51 days in those treated with acyclovir.25 In a direct comparison of valacyclovir and famciclovir, resolution of rash and pain times were found comparable.26 Table 218,27 summarizes the current recommendations for antiviral therapy in patients with HZ.
Pain Management
Pain is almost universal once the HZ rash appears. Pain associated with the prodromal period is variable but may be present in 70% to 80% of patients.28,29 The severity of acute pain in HZ is highly variable, ranging from mild to quite severe. Pain can begin weeks or a single day before the rash emerges and persist for several weeks after the rash disappears.
Aggressive pain management is appropriate. A variety of opiate analgesics (eg, hydrocodone, oxycodone, hydromorphone, morphine) and nonopiate analgesics (acetaminophen, NSAIDs) may be effective.17,28 Drug choices, dosage, and scheduling should be tailored to the patient’s level of pain and disability, with any potential contraindications also taken into account. Mild pain can be treated with as-needed dosing, whereas scheduled dosing is preferred for moderate to severe pain.16
If acute pain persists, addition of gabapentin, pregabalin, or nortriptyline is reasonable.17,22,28,30 Although these medications have been studied in the treatment of postherpetic neuralgia (PHN), there is little evidence to support their use for acute zoster pain.22,30
Additional interventions that have been studied for relief of acute HZ pain include topical lidocaine, acupuncture, and interventional pain injections. However, the evidence is either scant or of poor quality. More research is needed before these modalities can be routinely recommended in the clinical setting.17,22
Corticosteroids have been used for acute HZ, but conflicting study results make their routine use controversial.17,31,32 In some studies, corticosteroids reduced acute pain and speeded lesion healing and return to daily activities; others have yielded little evidence to support these findings.22,33 Corticosteroids may offer the greatest benefit when used in combination with effective antiviral therapy.18,22,31,32 In one randomized clinical trial comparing acyclovir with acyclovir plus prednisolone (40 mg/d for three weeks, tapered down) combination therapy was associated with a significant decrease in pain during the initial two weeks.32
Historically, corticosteroids have also been prescribed with the hope that their anti-inflammatory properties might help reduce the risk for PHN. However, a recent Cochrane Review found that these agents do not reliably prevent PHN six months after HZ rash onset.34 Glucocorticoids may improve motor outcomes and acute pain in VZV-induced facial paralysis and cranial polyneuritis, in which compression of affected nerves may contribute to disability.
Before prescribing steroids, clinicians must consider contraindications to their use, including diabetes, osteoporosis, hypertension, glaucoma, and gastritis.16
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