- Caused by herpes-zoster (shingles) infection.
Herpes-zoster infections affect 1.25/1000 people.
Elderly approximately 20X more likely to be affected.
Patients with malignancies, especially lymphoproliferative disorders are at increased risk.
- Prevalence rates of post-herpetic neuralgia range from 9 to 34%.
a. 65% of patients above age 60 have pain for more than a month.
b. 75% of patients above age 70 have pain for more than a month.
c. 50% of patients above age 60 have pain for more than a year!
- Burning and/or lancinating pain in the distribution of a previous herpes-zoster rash.
Healing or healed rash usually apparent.
Patients may have abnormal sensation in this distribution.
- Most common areas affected in the elderly are the thoracic area and the ophthalmic division of the trigeminal nerve.
- No special testing needed
- Antidepressants - Tricyclics (Elavil) are the most studied group for PHN.
Antiepileptics - Gabapentin (Neurontin) is good for the lancinating pains, has a good side effect profile for the elderly. Also unlike other anti-convulsants, it has no hepatotoxicity, does not cause blood dyscrasias and has few drug interactions. Lidoderm patches may be of some symptomatic value. (after lesions
heal) Sympathetic nerve blocks - may be valuable even in long term patients.
Radiofrequency rhizotomies in refractory cases.
- Intrathecal steroids - a relatively new but promising treatment.