eMedicine Specialties > Neurology > Headache and Pain

Postherpetic Neuralgia

Author: W Alvin McElveen, MD, Director, Stroke Unit, Lakewood Ranch Medical Center; Neurologist, Manatee Memorial Hospital
Coauthor(s): Ralph F Gonzalez, MD, Private Practice, Bradenton Neurology, Inc; Consulting Staff, Department of Neurology, Blake Hospital, Lakewood Ranch Medical Center, Manatee Memorial Hospital; Douglas Sinclair, DO, Consulting Staff, Department of Neurology, Blake Medical Center and Bradenton Neurology, Inc
Contributor Information and Disclosures

Updated: Jan 8, 2010

Introduction

Background

Herpes zoster (HZ) is a viral infection that usually presents as a childhood infection of varicella (ie, chicken pox). The pathogen is human herpesvirus-3 (HHV-3), also known as the varicella zoster virus (VZV). Following the acute phase, the virus enters the sensory nervous system, where it is harbored in the geniculate, trigeminal, or dorsal root ganglia and remains dormant for many years. With advancing age or immunocompromised states, the virus reactivates and an eruption (ie, shingles) occurs. Even after the acute rash subsides, pain can persist or recur in shingles-affected areas. This condition is known as postherpetic neuralgia (PHN).

Pathophysiology

Some patients with postherpetic neuralgia (PHN) appear to have abnormal function of unmyelinated nociceptors and sensory loss (usually minimal). Pain and temperature detection systems are hypersensitive to light mechanical stimulation, leading to severe pain (allodynia). Allodynia may be related to formation of new connections involving central pain transmission neurons. Other patients with PHN may have severe, spontaneous pain without allodynia, possibly secondary to increased spontaneous activity in deafferented central neurons or reorganization of central connections. An imbalance involving loss of large inhibitory fibers and an intact or increased number of small excitatory fibers has been suggested. This input on an abnormal dorsal horn containing deafferented hypersensitive neurons supports the clinical observation that both central and peripheral areas are involved in the production of pain.

Frequency

United States

Frequency 1 month after onset of shingles is 9-14.3% and at 3 months is about 5%. At 1 year, 3% continue to have severe pain.

Family history as a risk factor for herpes zoster has been described. In a case-control study of 504 patients and 523 controls, Hicks et al found that the patients were more likely to report blood relatives with herpes zoster than the controls (39% vs 11%, p<.001). This risk was higher in patients with multiple blood relatives with herpes zoster compared with those with a single blood relative with herpes zoster.1

International

A study from Iceland demonstrated variations in risk of PHN associated with different age groups. No patient younger than 50 years described severe pain at any time. Patients older than 60 years described severe pain: 6% at 1 month and 4% at 3 months from the onset of shingles.2

Mortality/Morbidity

  • Postherpetic neuralgia is not fatal.
  • Patients may experience significant pain for a prolonged period of time.
  • Older age appears to be the most significant risk factor for developing PHN.

Sex

No predilection for developing PHN is known. Although 65% of patients in a study by Watson et al were women, this was believed to mirror the usual predominance of women in this age group.

Age

The association between greater age and PHN is strong.3 At age 60 years, approximately 60% of patients with shingles develop PHN, and at age 70 years, 75% develop PHN.

Clinical

History

  • A painful vesicular eruption in a dermatomal distribution is typical of herpes zoster (HZ).
  • With resolution of the eruption, pain that continues for 3 months or more is defined as postherpetic neuralgia (PHN).
  • Pain is intense and may be described as burning, stabbing, or gnawing.
  • HZ can reactivate subclinically with pain in a dermatomal distribution without rash.4 This condition is known as zoster sine herpete and may be more complicated, affecting multiple levels of the nervous system and causing multiple cranial neuropathies, polyneuritis, myelitis, or aseptic meningitis.5

Physical

  • Area of previous HZ may show evidence of cutaneous scarring.
  • Sensation may be altered over involved areas, in the form of either hypersensitivity or decreased sensation.
  • Allodynia is pain produced by a non-noxious stimulus, such as a light touch by a brush, and may be present over the involved area.
  • Changes in autonomic function such as increased sweating over the involved area may be seen.

Causes

  • Risk factors for development of PHN include the following:
    • Advancing age
    • Site of HZ involvement
      • Lower risk - Jaw, neck, sacral, and lumbar
      • Moderate risk - Thoracic
      • Highest risk - Trigeminal (especially ophthalmic division), brachial plexus
    • Severe prodromal pain (with HZ)
    • Severe rash

More on Postherpetic Neuralgia

Overview: Postherpetic Neuralgia
Differential Diagnoses & Workup: Postherpetic Neuralgia
Treatment & Medication: Postherpetic Neuralgia
Follow-up: Postherpetic Neuralgia
Multimedia: Postherpetic Neuralgia
References
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References

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  2. Helgason S, Petursson G, Gudmundsson S, Sigurdsson JA. Prevalence of postherpetic neuralgia after a first episode of herpes zoster: prospective study with long term follow up. BMJ. Sep 30 2000;321(7264):794-6. [Medline].

  3. Delaney A, Colvin LA, Fallon MT, et al. Postherpetic neuralgia: from preclinical models to the clinic. Neurotherapeutics. Oct 2009;6(4):630-7. [Medline].

  4. Gilden D, Nagel MA, Mahalingam R, et al. Clinical and molecular aspects of varicella zoster virus infection. Future Neurol. Jan 1 2009;4(1):103-117. [Medline].

  5. Spiegel R, Miron D, Lumelsky D, Horovitz Y. Severe Meningoencephalitis Due to Late Reactivation of Varicella-Zoster Virus in an Immunocompetent Child. J Child Neurol. Jun 3 2009;[Medline].

  6. Haanpaa M, Dastidar P, Weinberg A, et al. CSF and MRI findings in patients with acute herpes zoster. Neurology. Nov 1998;51(5):1405-11. [Medline].

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  9. [Best Evidence] Chen JY, Chang CY, Feng PH, Chu CC, So EC, Hu ML. Plasma vitamin C is lower in postherpetic neuralgia patients and administration of vitamin C reduces spontaneous pain but not brush-evoked pain. Clin J Pain. Sep 2009;25(7):562-9. [Medline].

  10. Benzon HT, Chekka K, Darnule A, Chung B, Wille O, Malik K. Evidence-based case report: the prevention and management of postherpetic neuralgia with emphasis on interventional procedures. Reg Anesth Pain Med. Sep-Oct 2009;34(5):514-21. [Medline].

  11. Gilron I, Bailey JM, Tu D, Holden RR, Jackson AC, Houlden RL. Nortriptyline and gabapentin, alone and in combination for neuropathic pain: a double-blind, randomised controlled crossover trial. Lancet. Oct 10 2009;374(9697):1252-61. [Medline].

  12. Baron R, Saguer M. Mechanical allodynia in postherpetic neuralgia: evidence for central mechanisms depending on nociceptive C-fiber degeneration. Neurology. Dec 1995;45(12 Suppl 8):S63-5. [Medline].

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  15. [Best Evidence] Freynhagen R, Strojek K, Griesing T, et al. Efficacy of pregabalin in neuropathic pain evaluated in a 12-week, randomised, double-blind, multicentre, placebo-controlled trial of flexible- and fixed-dose regimens. Pain. Jun 2005;115(3):254-63. [Medline].

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  18. Merritt HH. A Textbook of Neurology. 1979;90. [Medline].

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  20. [Best Evidence] Oxman MN, Levin MJ, Johnson GR, et al. A vaccine to prevent herpes zoster and postherpetic neuralgia in older adults. N Engl J Med. Jun 2 2005;352(22):2271-84. [Medline].

  21. Rath SA, Braun V, Soliman N, et al. Results of DREZ coagulations for pain related to plexus lesions, spinal cord injuries and postherpetic neuralgia. Acta Neurochir (Wien). 1996;138(4):364-9. [Medline].

  22. Rowbotham M, Harden N, Stacey B, et al. Gabapentin for the treatment of postherpetic neuralgia: a randomized controlled trial. JAMA. Dec 2 1998;280(21):1837-42. [Medline].

  23. Rowbotham MC, Davies PS, Fields HL. Topical lidocaine gel relieves postherpetic neuralgia. Ann Neurol. Feb 1995;37(2):246-53. [Medline].

  24. Tyring S, Barbarash RA, Nahlik JE, et al. Famciclovir for the treatment of acute herpes zoster: effects on acute disease and postherpetic neuralgia. A randomized, double-blind, placebo-controlled trial. Collaborative Famciclovir Herpes Zoster Study Group. Ann Intern Med. Jul 15 1995;123(2):89-96. [Medline].

  25. Watson CP. Postherpetic neuralgia. Neurol Clin. May 1989;7(2):231-48. [Medline].

  26. Watson CP, Vernich L, Chipman M, Reed K. Nortriptyline versus amitriptyline in postherpetic neuralgia: a randomized trial. Neurology. Oct 1998;51(4):1166-71. [Medline].

  27. Watson CPN, Gershon AA. Herpes Zoster and Post Herpetic Neuralgia. Vol 11. 2001:90-93, 108-109.

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Further Reading

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Keywords

postherpetic neuralgia, herpes zoster, HZ, varicella zoster, chicken pox, shingles, zoster sine herpete, ZSH, human herpesvirus-3, HHV-3, varicella-zoster virus, VZV, PHN, post-herpetic neuralgia, viral infection

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Contributor Information and Disclosures

Author

W Alvin McElveen, MD, Director, Stroke Unit, Lakewood Ranch Medical Center; Neurologist, Manatee Memorial Hospital
W Alvin McElveen, MD is a member of the following medical societies: American Academy of Neurology, American Medical Association, American Society of Neuroimaging, American Stroke Association, and Southern Clinical Neurological Society
Disclosure: Nothing to disclose.

Coauthor(s)

Ralph F Gonzalez, MD, Private Practice, Bradenton Neurology, Inc; Consulting Staff, Department of Neurology, Blake Hospital, Lakewood Ranch Medical Center, Manatee Memorial Hospital
Ralph F Gonzalez, MD is a member of the following medical societies: American Academy of Neurology and Florida Medical Association
Disclosure: Nothing to disclose.

Douglas Sinclair, DO, Consulting Staff, Department of Neurology, Blake Medical Center and Bradenton Neurology, Inc
Disclosure: Nothing to disclose.

Medical Editor

Joseph Carcione Jr, DO, MBA, Consultant in Neurology and Medical Acupuncture, Medical Management and Organizational Consulting, Central Westchester Neuromuscular Care, PC; Medical Director, Oxford Health Plans
Joseph Carcione Jr, DO, MBA is a member of the following medical societies: American Academy of Neurology
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

James H Halsey, MD, Professor, Department of Neurology, University of Alabama Medical Center
James H Halsey, MD is a member of the following medical societies: American Academy of Neurology, American Heart Association, American Medical Association, American Neurological Association, American Society of Neuroimaging, Medical Association of the State of Alabama, New York Academy of Sciences, Pan American Medical Association, Sigma Xi, Society for Neuroscience, and Southern Medical Association
Disclosure: Nothing to disclose.

CME Editor

Selim R Benbadis, MD, Professor, Director of Comprehensive Epilepsy Program, Departments of Neurology and Neurosurgery, University of South Florida School of Medicine, Tampa General Hospital
Selim R Benbadis, MD is a member of the following medical societies: American Academy of Neurology, American Academy of Sleep Medicine, American Clinical Neurophysiology Society, American Epilepsy Society, and American Medical Association
Disclosure: Nothing to disclose.

Chief Editor

Robert A Egan, MD, Director of Neuro-Ophthalmology, St Helena Hospital
Robert A Egan, MD is a member of the following medical societies: American Academy of Neurology, American Heart Association, North American Neuro-Ophthalmology Society, and Oregon Medical Association
Disclosure: Nothing to disclose.

 
 
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