Herpes zoster virus
Herpes zoster virus, also known as varicella-zoster virus (VZV), is the same virus responsible for chickenpox. After an individual contracts chickenpox or receives the chickenpox vaccine, the virus becomes dormant in the nerve cells and can reactivate later in life, leading to herpes zoster, commonly referred to as shingles. This condition is particularly prevalent in older adults and those with weakened immune systems, such as cancer patients or organ transplant recipients. Symptoms typically begin with pain and burning sensations on one side of the body, followed by the appearance of a rash and blisters that may ooze and crust over.
The incidence of herpes zoster is significant, with about one million cases reported annually in the United States. While the condition usually resolves within a few weeks, complications like postherpetic neuralgia can cause prolonged pain. Antiviral medications, such as Acyclovir, are often used to lessen symptoms and prevent complications, especially if initiated early. Vaccines like Zostavax and Shingrix are recommended for older adults to reduce the risk of developing shingles. Understanding herpes zoster is vital due to its potential to cause pain and complications, especially in vulnerable populations.
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Herpes zoster virus
ALSO KNOWN AS: Varicella-zoster virus (VZV)
Related condition:Shingles
DEFINITION: Herpes zoster is an infection caused by the same virus that causes chickenpox, the varicella-zoster virus (VZV). This virus remains in the nerve cells for life in people who had chickenpox or received the chickenpox vaccine. The virus reappears as herpes zoster (shingles) later in life, particularly in older adults and immunocompromised persons. The virus is reactivated because the body loses its immunity to the varicella-zoster virus over time.
Risk factors: Because of their altered immunity, people with certain types of cancers are at an increased risk of developing herpes zoster. People who have had chickenpox or the chickenpox live-virus vaccine are at risk and risk increases with age. Individuals over fifty, those undergoing chenotherapy, and organ transplant recipients are at anincreased risk.
Etiology and the disease process: Herpes zoster results when the latent VZV within the sensory ganglia is reactivated.
The first signs of the disease are pain and a burning sensation on one side of the body. These symptoms may last up to five days. Then, the skin reddens, and blisters form on the affected side of the body. Within seven to ten days, the blisters will ooze and crust and begin to heal. The whole disease process takes up to five weeks.
The reactivation of VZV is higher in cancer patients because cell-mediated immunity is deficient in these patients due to chemotherapy or the disease itself. Also, a Russian case study found that the whole disease process is generally longer in cancer patients. Nevertheless, some research shows that older cancer patients who were vaccinated against herpes zoster before undergoing chemotherapy were more than 40 percent less likely to develop it than those who were unvaccinated.
Because the infection affects the nerves, herpes zoster can be painful. A common complication that occurs in one-third of older patients is postherpetic neuralgia (PHN), as noted by the CDC. In postherpetic neuralgia patients, the rash and the pain are severe and last for months.
Incidence: Each year, about a million cases of herpes zoster are reported in the United States. The annual incidence of herpes zoster is about four per thousand persons for the general population and ten per thousand for those over age sixty.
Symptoms: Herpes zoster is accompanied by pain in one side of the body, along with tingling and a burning sensation. The skin reddens, and blisters appear. The small blisters are dense and deep and may ooze and crust. Other symptoms include headache, fever, chills, abdominal pain, joint pain, lymph node swelling, hearing loss, genital lesions, vision and taste problems, and a general feeling of malaise.
Screening and diagnosis: The skin blisters and a prior history of varicella or shingles are the basis for diagnosis. Tests are rarely used, but tests like a viral culture of a blister can identify the herpes zoster virus. Other tests include:
- Tzanck test: The sore on the skin is scarred, and the sample is stained for examination under a microscope.
- Complete blood count (CBC): The blood is tested for nonspecific signs of infection, such as an elevated number of white blood cells.
- Immunoglobulin measurement: Blood is tested to measure the level of varicella antibodies.
Treatment and therapy: Although the disease disappears after a few weeks, treatment is usually necessary for pain. The antiviral medication Acyclovir (Zovirax) reduces pain and complications and protects immunocompromised individuals such as cancer patients. Other medicines that can be used are Famciclovir (Famvir) and Valacyclovir (Valtrex).
Treatment with these drugs should begin within seventy-two hours of the initial signs and, if possible, before blistering. Although these drugs are generally given as pills, some cancer patients may require intravenous acyclovir therapy if they are severely immunocompromised. Other suggestions for treatment are as follows:
- Control the pain with analgesics and the itching with antihistamines.
- Use a capsaicin-containing cream to prevent postherpetic neuralgia.
- Keep the affected skin covered and dry.
- Keep skin clean and do not reuse contaminated items.
- Rest in bed and avoid contact with others.
Prognosis, prevention, and outcomes: Usually, herpes zoster lesions heal within two to three weeks after the first signs appear. Patients, especially older adults, may experience temporary or permanent weakness or paralysis or develop continued nerve pain that persists for years. If the eyes are affected, the person may become blind if not treated.
In 2006, a live zoster vaccine called Zostavax was licensed and recommended for routine administration to adults over sixty. However, the vaccine is not recommended for people taking immunosuppressive therapy, including high-dose corticosteroids, or for people with primary or acquired immunodeficiency states, including leukemia, lymphoma of any type, other malignant neoplasms affecting the bone marrow or lymphatic system, acquired immunodeficiency (AIDS), or other clinical manifestations of infection with human immunodeficiency viruses. In 2017, the vaccine Shingrix became available. Shingrix is more appropriate for individuals with compromised immune systems.
Bibliography
American Academy of Pediatrics. “Varicella-Zoster Virus Infections.” Red Book: 2021-2024 Report of the Committee on Infectious Diseases. Kimberlin, David W., et al. 32nd ed. American Academy of Pediatrics, 2021. doi.org/10.1542/9781610025782-S3‗156.
Bogomolov, B. P., and E. G. Bakhur. “Herpes Zoster in Cancer Patients.” Ter Arkh 62.1 (1990): 99–103.
"Infections in People with Cancer." American Cancer Society, www.cancer.org/cancer/managing-cancer/side-effects/infections.html. Accessed 30 June 2024.
National Center for Immunization and Respiratory Diseases, Division of Viral Diseases. "Shingles (Herpes Zoster)." Centers for Disease Control and Prevention, www.cdc.gov/shingles/index.html. Accessed 30 June 2024.
Permanente, Kaiser. "Shingles Vaccine Still Effective after Chemotherapy." Science News, 2014, www.sciencedaily.com/releases/2014/08/140805132005.htm. Accessed 30 June 2024.
"Recombinant Zoster (Shingles) Vaccine (RZV)." MedlinePlus, medlineplus.gov/druginfo/meds/a618023.html. Accessed 30 June 2024.
Siegel, Mary-Ellen, and Gray Williams. Shingles: New Hope for an Old Disease. Rev. ed. Evans, 2008.