Shingles (also known as herpes zoster) is a painful, blistering rash typically occurring in a stripe-like pattern.
It always involves only one side of the body, and does not cross the midline in either the front or back. The rash usually heals in 2-4 weeks, but in some cases the involved nerves are damaged, and the pain persists.
This condition, called postherpetic neuralgia, may last for years.
A person who develops shingles must first have had chickenpox. For unknown reasons, the virus of chickenpox (varicella-zoster virus) may never completely leave the body. Instead, it may remain in a dormant state in the dorsal nerve roots of the spinal cord.
Then, after a period of many years, the virus becomes reactivated, traveling along the nerve to the nerve endings in the skin, resulting in the blistering rash. The outbreak occurs in the area of skin innervated by the specific nerve root; hence, the stripe-like appearance involving only one side of the body.
The cause of the viral reactivation is poorly understood, but is thought to be due to weakening of the immune system, as in the elderly, those stricken with cancer or other serious illness, or those under extreme stress.
There are several antiviral agents available for the treatment of shingles, including Valtrex, Zovirax, and Famvir. These drugs provide best results when started within 72 hours of the appearance of the characteristic skin eruption.
There is no real evidence that steroids provide any added benefit, or that they decrease the likelihood of developing postherpetic neuralgia.
In those between age 50 and 80, the shingles vaccine will decrease the chance of an outbreak by roughly 50 percent. The vaccine also decreases rates of PHN, and if an outbreak occurs, its severity.
It is important to note that a person who has not had chickenpox can contract the disease from one who has shingles, but shingles does not spread from one person to another.
(Dr. Robert Sweeten, M.D., is a family physician in Neosho. He can be reached at 417-451-7425.)