Cause for Herpes Zoster

The cause for herpes zoster is a reinfection with the varicella-zoster virus. This is the same virus that causes chickenpox. While both illnesses are caused by the same virus, herpes zoster occurs due to a reactivation of the virus. Among the things that can put a person at risk of developing this condition are having had chickenpox or the chickenpox vaccine, as well as having a weakened immune system due to HIV infection, chemotherapy or radiation treatment, transplant operations, or stress.

 

What Causes Herpes Zoster?

There is only one cause for herpes zoster (also known as shingles). Herpes zoster is caused by a reinfection with the varicella-zoster virus. The varicella-zoster virus that causes this condition is the same virus that causes chickenpox. The infection with this virus tends to occur during different decades of a person's life.
 

The Varicella-Zoster Virus: The Cause of Herpes Zoster

Varicella-zoster is part of the herpesvirus family. This group of viruses includes the herpes simplex virus (HSV) that causes cold sores, fever, blisters, genital herpes (a sexually transmitted disease), and the Epstein-Barr virus involved in infectious mononucleosis.
 
As early as 1909, a German scientist suspected that the viruses causing chickenpox and herpes zoster were one and the same. In the 1920s and 1930s, the case was strengthened. As part of an experiment, children were inoculated with fluid from the lesions of patients with herpes zoster. Within two weeks, about half the children came down with chickenpox. Finally, in 1958, detailed analyses of the viruses taken from patients with either chickenpox or herpes zoster confirmed that the viruses were identical.
 
So how does the same virus that causes chickenpox also cause herpes zoster? To understand this, it may be helpful to understand the "reactivation" of the varicella-zoster virus.
 
(Cause for Herpes Zoster Continued: Page 2)
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Written by/reviewed by: Arthur Schoenstadt, MD
Last reviewed by: Arthur Schoenstadt, MD