Postherpetic Neuralgia

1. See Also
   1. Herpes Zoster
   2. Zoster Ophthalmicus
2. Epidemiology
   1. Incidence following Herpes Zoster
      1. Age over 80 years: 30%
      2. Age 60-65 years: 20%
      3. Age <50 years: Rare
3. Pathophysiology
   1. Complication following Herpes Zoster infection
   2. Virus replication destroys basal ganglia
4. Risk Factors
   1. Advanced age
   2. Female gender
   3. Severe rash
   4. Severe acute pain with the acute zoster outbreak
   5. Prodromal pain prior to acute rash development
   6. Zoster Ophthalmicus
5. Symptoms
   1. Persistent pain in dermatomal distribution
6. Management: Topical
   1. Lidocaine 5% ointment (Xylocaine)
      1. Apply (up to 3 patches/day) to affected area every 4-12 hours prn
   2. Capsaicin cream (Zostrix) 0.075% cream
      1. Apply to affected area three to four times daily
7. Management: Neuro-Psychiatric medications
   1. General
      1. Amitriptyline more effective than Gabapentin
      2. Adverse effects limit this class
      3. Gnann (2002) N Engl J Med 347:340
   2. Tricyclic Antidepressants
      1. Agents
         1. Amitriptyline (Elavil)
         2. Nortriptyline (Pamelor)
         3. Imipramine (Tofranil)
         4. Desipramine (Norpramin)
      2. Efficacy
         1. As effective and better tolerated than Narcotics
         2. Raja (2002) Neurology 59:1015-21
   3. Serotonin-Norepinephrine Reuptake Inhibitors (SNRI)
      1. Cymbalta
      2. Venlafaxine
   4. Anticonvulsants
      1. Gabapentin (Neurontin)
      2. Pregabalin (Lyrica)
8. Management: Refractory Postherpetic Neuralgia
   1. See also Chronic Pain Management
   2. Transcutaneous Electric Nerve Stimulation (TENS)
   3. Biofeedback
   4. Nerve Block
   5. OpioidAnalgesics
   6. Intrathecal Methylprednisolone 60 mg at L2-L3
      1. Good to excellent pain relief in refractory cases
      2. Relief persists longer than 2 years
      3. References
         1. Kotani (2000) N Engl J Med 343:1514-9
9. Course
   1. Duration: 30 days to 6 months
10. Prevention
    1. See Herpes Zoster
    2. Herpes Zoster Vccine (Zostavax)
11. References
    1. Fashner (2011) Am Fam Physician 83(12): 1432-7
    2. Kost (1996) N Engl J Med 335:32-42
    3. Rowbotham (1998) JAMA 28:1837-42
    4. Stankus (2000) Am Fam Physician 61(8):2437-44