Understanding Shingles -- the Basics

Medically Reviewed by Sabrina Felson, MD on April 21, 2021

What Is Shingles?

Shingles (herpes zoster) results from a reactivation of the varicella-zoster virus that also causes chickenpox. With shingles, usually the first thing you may notice is a tingling sensation or burning pain on one side of your body or face. You may also feel under the weather, and notice enlarged lymph nodes. Within days, tiny clusters of red bumps quickly evolve into a group of painful blisters which can pop and get crusty with pus. Unless you are immunocompromised, the rash almost never crosses the midline of your body (it’s unilateral) because it is localized to one nerve root.

The area can be very painful, itchy, and tender. After one to two weeks, the blisters heal and form scabs.

Up to 15% of people with herpes zoster develop deep pain called postherpetic neuralgia that follows after the infection has run its course. It can continue for months or even years, especially in older people. The incidence of shingles and of postherpetic neuralgia rises with increasing age. In fact, more than 50% of cases occur in people over age 60. 

Shingles usually occurs only once, although it has been known to recur, usually in people with weakened immune systems. 


What Causes Shingles?

Shingles arises from varicella-zoster, the same virus that causes chickenpox. Following a bout of chickenpox, the virus lies dormant in the spinal nerve cells. But it can be reactivated years later when the immune system is suppressed by:

  • Physical or emotional trauma
  • A serious illness
  • Certain medications, like steroids

Medical science doesn't understand why the virus becomes reactivated in some people and not in others.

WebMD Medical Reference



National Institute of Neurologic Disorders and Stroke: "Shingles. Seek Early Treatment."

Mayo Clinic Health Letter, June 2002.

Oxman M. New England Journal of Medicine, June 2, 2005.

Douglas M. Drug Safety,  2004.

WebMD Health News: "Shingles Vaccine to Be Routine at 60."

FDA: "FDA Licenses New Vaccine to Reduce Older Americans' Risk of Shingles."




© 2021 WebMD, LLC. All rights reserved.
Click to view privacy policy and trust info