If you suddenly develop severe pain in a limited area on one side of your body, you may have shingles and need treatment immediately to prevent that pain from lasting for the rest of your life. Shingles is Chicken Pox the second time around. It's called postherpetic neuralgia and when you have severe pain that is not caused by an injury and your doctor cannot find a cause, you should get a blood test for herpes zoster and start taking Famvir or Valtrex immediately to prevent the pain from becoming permanent.

The first time you get chicken pox, blisters form over most of your body. After a week, your immunity drives the chicken pox virus from your bloodstream, but it remains in your nerve roots for the rest of your life. One of every in six people who get chicken pox will have the virus escape from nerves many years later to cause painful grouped blisters on the skin over the infected nerve on one side of the body.

If you wait for characteristic blisters to form, it may be too late to prevent the pain from lasting the rest of your life. Fifty percent of people over 60 who develop shingles, and are not treated, will suffer from post-herpetic neuralgia and have severe pain in that nerve for the rest of their lives, while fewer than seven percent treated with acyclovir will suffer permanent pain. Cortisones offer little protection. If you develop postherpetic neuralgia, your pain can be treated with a .025% capsaicin (pepper) cream and tegretol or gabapentin anticonvulsant pills. A report in the New England Journal of Medicine offers a more effective treatment for post-herpetic neuralgia: 60 mg of methyl prednisone, injected directly into the spinal fluid, once a week for four weeks, lessens and even cures the pain.