Shingles and Post Herpetic Neuralgia

Most adults in the United States managed to get chickenpox as children, in fact almost 95% of us. The varicella zoster (herpes) virus was the infectious culprit of our chickenpox and unfortunately remains a time bomb for many of us. What is remarkable about this little virus is that long after our chickenpox has resolved, the virus remains in our bodies. The virus hides in our dorsal root ganglia-nerve terminals near our spinal cords, and usually does nothing for many years… but continues ticking. These viral “bombs” can be triggered as we reach more advanced age or if we become immunocompromised from disease or medication. When we are most vulnerable, the viruses explode in a reproductive frenzy – often destroying their cozy dorsal ganglion homes, and travel along their associated nerves to the skin, damaging the nerves as they go.

The outcome of this explosion is an outbreak of a cutaneous rash and a condition called shingles. There are approximately one million new cases each year in the United States. Pain, itching, or tingling where the rash is destined to develop in a few days typically heralds the reactivation of the virus. The patient may also have symptoms consistent with a viral infection with headache, chills, malaise and occasional photophobia. A blistered rash typically appears on one side of the body along a well-defined strip of skin (a “dermatome”) and involves the thorax (chest, back, abdomen) or less commonly the face. The rash is erythematous and raised with clusters of clear vesicles. These vesicles will form over roughly a week and then crust over with drying and ultimately healing.

Unfortunately, for up to 20-30% of patients, a painful condition called “post herpetic neuralgia” (PHN) will develop. These patients will have varying degrees of burning and lancinating pain that can last weeks to many years. The pain of PHN can be very intense and often makes even the lightest touch to the area excruciating. We believe that there is likely a correlation between the degree of disruption of normal anatomy from the virus and the degree of pain. The visible viral disruption of the skin may be the “tip of the iceberg” for the overall damage that has occurred.  The ganglion near the spinal cord, which is not visible, can create terrible pain problems because of its important pain modulating function.

Treatment of PHN can be very frustrating, as we are dealing with severely damaged nerves that may be destined to send pain signals forever. The neuropathic (nerve pain) that arises often requires a multi-drug regimen including topical agents, anticonvulsants, antidepressants, anti-inflammatories and narcotics. In spite of strong medications and expert care, medical treatment fails to adequately treat pain in 40-50% of PHN patients. If medical management fails, more aggressive treatment with peripheral nerve stimulation can be utilized. Peripheral nerve stimulators are placed under the skin and apply electrical stimulation painful to nerves, decreasing transmission of pain impulses and often making the patient much more comfortable.

What is very clear is that PHN is a very troublesome pain problem and the best situation is to avoid an outbreak in the first place. There is now a vaccine (Zostavax) for those over 60 years of age to help prevent shingles and hence PHN. It appears the occurrence of shingles is reduced overall by about 50% with the vaccine. This is a huge benefit given the large number of new cases each year. If one does have an outbreak of shingles, the incidence of PHN can be dramatically reduced by early treatment with anti-viral drugs. The patient needs to be alert to the early prodromal symptoms and notify their physician if shingles is suspected…a day or two matters!

Most of us have had the dubious opportunity to contract chicken pox and therefore are “at risk” for shingles and post herpetic neuralgia. Remember, it is far better to prevent contracting herpes than trying to treat it. Talk to your physician about whether you are a candidate for the vaccine. If you already have contracted shingles, be alert to the early symptoms and get rapid treatment through your primary physician. Lastly, if you already have post herpetic neuralgia, get expert help for its management.