Postherpetic Neuralgia

Hello:

I am 47 years of age and have had outbreaks of shingles since 2004. The rash has always been located on my left buttock and no where else. With every outbreak I always took the anti-viral Valtrex which certainly shortened and helped the episodes. This past March, 2008, I had another outbreak in the same area. Unfortunately I didn't take the Valtrex and ended up suffering with the virus much longer. Now, just about a week ago, I've started to feel tingling and slight numbness in my lower legs and feet. Tingling also in my hands along with odd aching-like "spot" pains in different areas such as the top of my foot, my hands and a burning pain in my lower arm. I also noted odd sensations in my mouth. Could this be Postherpetic Neuralgia? Your help is greatly appreciated.

DB898  

[DrKalraMD]

Hi, post herpetic neuralgia is usually confined to specific location only, in your case it is quite generalized which could be either due to low vitamin B levels, low calcium etc.

Treatment of post herpetic neuralgia are  antidepressants, anticonvulsants (such as gabapentin or pregabalin) and topical agents such as lidocaine patches or capsaicin lotion. Opioid analgesics may also be appropriate in many situations. For more information visit http://en.wikipedia.org/wiki/Postherpetic_neuralgia

[kasbb86]

I am a 54 yr old male, in pretty good shape, non-smoker, non-drinker.  For the past 2 years I have experienced pain in the left side of my chest with tingling in the left arm.  I've seen 2 cardiologists and had a complete exam including an angiogram, showing no heart disease.  Since then I've seen gastroenterologists, pulmonologists, and pain specialists.  
My new doctor suggested PHN and tested me for the virus anitbody, which I have.  But I have never had any outbreak of shingles on the skin.  I've been on 300 mg of Gabapentin for 3 weeks now, and am using Capcaicin, but still have pain.  It feels like it's getting progressively worse.
I'm not so sure about my Doctor's diagnosis.  How can I know for certain?
How long does Gabapentin need to take effect?  
Would  a nerve block positively confirm the PNH diagnosis?
Any other tests to confirm this diagnosis?
Thank you.