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Shingles and chickenpox (Varicella-zoster virus) - Introduction

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of shingles and chickenpox.

Alternative Names

Chicken pox; Herpes zoster; Postherpatic neuralgia

Introduction:

Shingles and chickenpox were once considered separate disorders. Researchers now know that they are both caused by a single virus of the herpes family, known as varicella-zoster virus (VZV). The word herpes is derived from the Greek word "herpein," which means "to creep," a reference to a characteristic pattern of skin eruptions. VZV is still referred to by separate terms:

Varicella: The primary infection that causes chickenpox
Herpes zoster: The reactivation of the virus that causes shingles

Varicella (Chickenpox). When patients with chickenpox cough or sneeze, they expel tiny droplets that carry the virus. If a person who has never had chickenpox or never been vaccinated inhales these particles, the virus enters the lungs. From here it passes into the bloodstream. When it is carried to the skin it produces the typical rash of chickenpox.

Chickenpox is caused by the varicella-zoster virus, a member of the herpes virus family. The same virus also causes herpes zoster, or shingles, in adults. Chickenpox is extremely contagious, and can be spread by direct contact, droplet transmission, and airborne transmission. Symptoms range from fever, headache, stomach ache, or loss of appetite before breaking out in the classic pox rash. The rash can consist of several hundred small, itchy, fluid-filled blisters over red spots on the skin. The blisters often appear first on the face, trunk, or scalp and then spread to other parts of the body

Herpes Zoster (Shingles). The varicella virus also travels to nerve cells called dorsal root ganglia. These are bundles of nerves that transmit sensory information from the skin to the brain. Here, the virus can hide from the immune system for years, often for a lifetime. This inactivity is called latency.

Shingles
Click the icon to see an image of shingles.

If the virus becomes active after being latent, it causes the disorder known as shingles. The virus in this later form is referred to as herpes zoster. The virus spreads in the ganglion and to the nerves connecting to it. Nerves most often affected are those in the face or the trunk. The virus can also spread to the spinal cord and into the bloodstream.

It is not clear why the varicella virus reactivates in some people but not in others. In many cases, the immune system has become impaired or suppressed from certain conditions such as AIDS, other immunodeficient diseases, or certain cancers or drugs that suppress the immune system. Aging itself increases the risk for shingles.

Other Herpes Viruses

The varicella-zoster virus belongs to a group of herpes viruses that includes eight human viruses (it also includes animal viruses). Herpes viruses are similar in shape and size and reproduce within the structure of a cell. The particular cell depends upon the specific virus. Human herpes viruses include herpes simplex virus 1 (HSV-1), which causes cold sores, and herpes simplex virus 2 (HSV-2), which causes genital herpes. Cytomegalovirus (CMV), which causes mononucleosis and retinitis, and Epstein-Barre Virus (EBV), another cause of mononucleosis, are also human herpes viruses.

All herpes viruses share some common properties, including a pattern of active symptoms followed by latent inactive periods that can last for months, years, or even a lifetime. [For more information, see In-Depth Report #52: Herpes simplex.]

Resources

www.cdc.gov -- Centers for Disease Control and Prevention
www.niaid.nih.gov -- National Institute of Allergy and Infectious Diseases
www.ninds.nih.gov -- National Institute of Neurological Disorders and Stroke
www.aan.com -- American Academy of Neurology
www.neuropathy.org -- Neuropathy Association

References

Advisory Committee on Immunization Practices. Recommended adult immunization schedule: United States, 2009. Ann Intern Med. 2009 Jan 6;150(1):40-4.

American Academy of Pediatrics Committee on Infectious Diseases. Prevention of varicella: recommendations for use of varicella vaccines in children, including a recommendation for a routine 2-dose varicella immunization schedule. Pediatrics. 2007 Jul;120(1):221-31.

American Academy of Pediatrics Committee on Infectious Diseases. Recommended immunization schedules for children and adolescents -- United States, 2007. Pediatrics. 2007 Jan;119(1):207-8.

Centers for Disease Control and Prevention (CDC). A new product (VariZIG) for postexposure prophylaxis of varicella available under an investigational new drug application expanded access protocol. MMWR Morb Mortal Wkly Rep. 2006 Mar 3;55(8):209-10.

Centers for Disease Control and Prevention (CDC); Advisory Committee on Immunization Practices (ACIP). Update: recommendations from the Advisory Committee on Immunization Practices (ACIP) regarding administration of combination MMRV vaccine. MMWR Morb Mortal Wkly Rep. 2008 Mar 14;57(10):258-60.

Chaves SS, Gargiullo P, Zhang JX, Civen R, Guris D, Mascola L, et al. Loss of vaccine-induced immunity to varicella over time. N Engl J Med. 2007 Mar 15;356(11):1121-9.

Davis MM, Marin M, Cowan AE, Guris D, Clark SJ. Physician attitudes regarding breakthrough varicella disease and a potential second dose of varicella vaccine. Pediatrics. 2007 Feb;119(2):258-64.

Harpaz R, Ortega-Sanchez IR, Seward JF; Advisory Committee on Immunization Practices (ACIP) Centers for Disease Control and Prevention (CDC). Prevention of herpes zoster: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 2008 Jun 6;57(RR-5):1-30.

Kimberlin DW, and Whitley RJ. Varicella-zoster vaccine for the prevention of herpes zoster. N Engl J Med. 2007 Mar 29;356(13):1338-43.

Marin M, Güris D, Chaves SS, Schmid S, Seward JF; Advisory Committee on Immunization Practices, Centers for Disease Control and Prevention (CDC). Prevention of varicella: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 2007 Jun 22;56(RR-4):1-40.

Marin M, Meissner HC, Seward JF. Varicella prevention in the United States: a review of successes and challenges. Pediatrics. 2008 Sep;122(3):e744-51.

Myers MG, Seward JF, LaRussa PS. Varicella-zoster virus. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Kliegman: Nelson Textbook of Pediatrics. 18th ed. Saunders; 2007:chap 250.

Quan D, Hammack BN, Kittelson J, Gilden DH. Improvement of postherpetic neuralgia after treatment with intravenous acyclovir followed by oral valacyclovir. Arch Neurol. 2006 Jul;63(7):940-2.

Sampathkumar P, Drage LA, Martin DP. Herpes zoster (shingles) and postherpetic neuralgia. Mayo Clin Proc. 2009 Mar;84(3):274-80.

Strangfeld A, Listing J, Herzer P, Liebhaber A, Rockwitz K, Richter C, et al. Risk of herpes zoster in patients with rheumatoid arthritis treated with anti-TNF-alpha agents. JAMA. 2009 Feb 18;301(7):737-44.

Tyring SK. Management of herpes zoster and postherpetic neuralgia. J Am Acad Dermatol. 2007 Dec;57(6 Suppl):S136-42.

Urman CO and Gottlieb AB. New viral vaccines for dermatologic disease. J Am Acad Dermatol. 2008 Mar;58(3):361-70.

Whitley RJ, Gnann JW Jr. Herpes zoster in the age of focused immunosuppressive therapy. JAMA. 2009 Feb 18;301(7):774-5.

Woolery WA. Herpes zoster virus vaccine. Geriatrics. 2008 Oct;63(10):6-9.

Reviewed last on: 5/21/2009
Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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