II. Epidemiology
-
Incidence following Herpes Zoster
- Age over 80 years: 30%
- Age 60-65 years: 20%
- Age <50 years: <10-18%
III. Pathophysiology
- Most common complication following Herpes Zoster infection
- Virus replication destroys Basal Ganglia
IV. Risk Factors
- Advanced age
- Female gender
- Severe prodrome or severe rash
- Severe acute pain with the acute zoster outbreak
- Prodromal pain prior to acute rash development
- Zoster Ophthalmicus
- Immunosuppression
- Diabetes Mellitus
- Systemic Lupus Erythematosus (SLE)
V. Symptoms
- Pain in Dermatomal Distribution persists >90 days after Herpes Zoster rash resolves
- Burning or electric-shock pain
- Hyperalgesia
- Allodynia
VI. Management: Topical
-
Lidocaine 5% patch (Xylocaine, or OTC 4% patch at $2/patch)
- Apply (up to 3 patches/day) to affected area for 12 hours of every 24 hours (must have 12 hours free)
- Expensive alternatives (e.g. ZTlido 1.8% at $9/patch), but unlikely to result in better efficacy
- (2018) presc lett 25(11): 66
- Evidence of benefit is marginal
-
Capsaicin cream (Zostrix) 0.075% cream
- Apply to affected area three to four times daily
- Also marginal evidence for use
VII. Management: Neuro-Psychiatric medications
-
General
- Amitriptyline more effective than Gabapentin, but adverse effects limits tricyclic use
- Gnann (2002) N Engl J Med 347:340 [PubMed]
-
Anticonvulsants
- Both Gabapentin and Pregabalin are effective (NNT 9, NNH 26)
- Gabapentin (Neurontin)
- Start at 300 mg orally three times daily
- Titrate up to 600 mg three times daily
- (Lyrica)
- Dosing 75 to 150 mg orally twice daily
-
Serotonin-Norepinephrine Reuptake Inhibitors (SNRI)
- SNRIs are effective (NNT 7, NNH 13)
- Duloxetine (Cymbalta)
- Start at 20 mg orally daily
- May titrate to 60 mg orally daily
- Venlafaxine (Effexor)
- Start Venlafaxine XR 75 to 150 mg orally daily
- May advance to Venlafaxine XR 225 mg orally daily
-
Tricyclic Antidepressants
- Agents
- Efficacy
- Tricyclic Antidepressants have similar efficacy to other agents (NNT 5, NNH 17)
- As effective and better tolerated than Opioids
- Raja (2002) Neurology 59:1015-21 [PubMed]
- References
VIII. Management: Refractory Postherpetic Neuralgia
- See also Chronic Pain Management
- Transcutaneous Electric Nerve Stimulation (TENS)
- Biofeedback
- Nerve Block
- Opioid Analgesics
- Intrathecal Methylprednisolone 60 mg at L2-L3
- Good to excellent pain relief in refractory cases
- Relief persists longer than 2 years
- References
IX. Course
- Typical duration: 30 days to 6 months
- Some cases may persist years
X. Prevention
XI. References
- Fashner (2011) Am Fam Physician 83(12): 1432-7 [PubMed]
- Jones (2026) Am Fam Physician 114(2): 164-72 [PubMed]
- Kost (1996) N Engl J Med 335:32-42 [PubMed]
- Rowbotham (1998) JAMA 28:1837-42 [PubMed]
- Saguil (2017) Am Fam Physician 96(10): 656-63 [PubMed]
- Stankus (2000) Am Fam Physician 61(8):2437-44 [PubMed]