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Treating herpes zoster and postherpetic neuralgia: An evidence-based approach

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Alternative modalities to reduce pain

Acupuncture and transcutaneous electrical nerve stimulation (TENS) have been tried for the relief of PHN without consistent evidence of efficacy. There are no significant adverse effects associated with these therapies; however, the cost of treatment may be an issue. Acupuncture is not covered by many insurance carriers. Mental-health interventions, including cognitive and behavioral therapy, might help with overall physical and emotional functioning and quality of life.

Key Point

Acupuncture and transcutaneous electrical nerve stimulation do not appear to be effective for PHN relief.

Invasive interventions

Researchers have examined several interventional modalities for treating PHN that is refractory to medication.

Sympathetic nerve blocks. Retrospective studies have shown that sympathetic nerve block provides short-term improvement in pain in 40% to 50% of patients with PHN.35

Intercostal nerve block has been reported to provide long-lasting pain relief in patients with thoracic PHN.36

Neuraxial use of intrathecal methylprednisone is supported by moderately good evidence of benefit in patients with intractable PHN.37 Because this intervention poses significant risk of neurologic sequelae, we do not recommend that it be used in clinical practice.

Spinal cord stimulation was studied prospectively in a case series of 28 patients.38 Long-term pain relief was obtained in 82%. Patients serve as their own controls by switching off the spinal cord stimulator and monitoring pain. Consider spinal cord stimulation for patients with well-established PHN that is refractory to conventional management.

Cryotherapy was used for facial neuralgia pain, without significant benefit.39 Another trial showed short-term benefit in 11 of 14 patients who underwent cryotherapy of the intercostal nerves for thoracic PHN.40

Botulinium toxin A injection. An abstract presented at the February 2010 meeting of the American Academy of Pain Medicine described how subcutaneous injection of botulinium toxin A reduced pain in patients with PHN, compared with lidocaine and placebo injections. The pain relief was noted in 1 week and persisted for 90 days.41

Surgery. Many surgical interventions have been described and used to treat PHN, but none has a role in clinical practice.

Key Point

Many surgical interventions have been used to treat PHN, but none has a role in clinical practice.

When should you refer to a pain management center?

Dermatomal pain that lasts for longer than 180 days after a herpes zoster rash can be considered “well-established PHN” to denote its refractory nature. As a primary care clinician, you can refer a patient with PHN to a pain management center at any stage of disease but especially when the:

  • patient has a significant medical comorbidity and you think that he or she requires the services of a specialist to manage multimodal pharmacotherapy

  • PHN pain is refractory to conventional treatment modalities

  • patient needs an invasive intervention
  • patient needs treatment with a high-dose capsaicin patch and you have not been trained to apply it.

Preventing herpes zoster and PHN

Obviously, preventing PHN is closely tied to preventing herpes zoster. To help prevent herpes zoster:

  • vaccinate children with varicella vaccine to prevent primary varicella infection42

  • use varicella-zoster immunoglobulin, as recommended by the CDC’s Advisory Committee on Immunization Practices (ACIP), in immunocompromised, seronegative patients who were exposed recently to a person with chickenpox or herpes zoster42

  • administer the herpes zoster vaccine to patients 60 years and older, as recommended by ACIP.43 The FDA recently approved use of this vaccine for people 50 through 59 years, but ACIP has not changed its recommendations.44

As we’ve discussed, herpes zoster vaccination, antiviral therapy, and aggressive pain control can reduce the incidence, severity, and duration of acute herpes zoster and PHN.

A large multicenter, randomized, placebo-controlled trial demonstrated that herpes zoster vaccine decreases the likelihood of developing herpes zoster in immunocompetent individuals 60 years and older.45 The vaccine reduced the incidence of herpes zoster by 51.3%; reduced the burden of illness by 61.1%; and reduced the incidence of PHN by 66.5%.45 The live, attenuated vaccine is contraindicated in children, pregnant women, and immunocompromised individuals.

The number needed to treat for herpes zoster vaccine is 175; that is, 1 case of herpes zoster is avoided for every 175 people vaccinated.1

Key Point

One case of herpes zoster is avoided for every 175 people vaccinated.

Newer tools mean a better outcome

We have improved our ability to diminish the incidence of herpes zoster and PHN and to manage postherpetic pain more effectively. These advances include the development of a herpes zoster vaccine; consensus that antiviral therapy and aggressive pain management can reduce the burden of PHN; identification of efficacious treatments for PHN; and recognition of PHN as a study model for neuropathic pain research.

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