Anyone who has had chicken pox can develop herpes zoster. Also known as shingles or zoster, herpes zoster is caused by the same virus as chicken pox. After the chicken pox clear, the virus remains dormant (inactive) within certain nerve cells of the body. When the virus reactivates, zoster, which can be quite painful, develops.
About 20 percent of people who have had chicken pox will get zoster. Most develop zoster only once.
CAUSES OF HERPES ZOSTER
It is not clear what reactivates or “awakens” the virus. A temporary weakness in immunity (the body’s ability to fight infection) may cause the virus to multiply and move along nerve fibers toward the skin. Although children can get zoster, it is more common in people over the age of 50. Illness, trauma, and stress also may trigger zoster.
We do know that people with a weakened immunity are prone to developing zoster. A variety of illnesses and medical treatments can weaken a person’s immunity. These include cancers, AIDS, treatment for cancer such as chemotherapy or radiation, drugs taken to prevent rejection of a transplanted organ, and cortisone when taken for a long time. All can make someone susceptible.
While much less contagious than chicken pox, a person with zoster can transmit the virus by means of direct skin contact if blisters break. Newborns and those with decreased immunity are at the highest risk. If someone contracts the virus, the person develops chicken pox – not zoster. Shingles only occurs after a person develops chicken pox and the virus re-emerges in certain nerve cells.
SIGNS AND SYMPTOMS OF HERPES ZOSTER
Zoster typically causes more pain and less itching than chicken pox. A person may feel burning, itching, tingling, or extreme sensitivity on the skin (usually limited to an area on one side of the body). These symptoms are typically present for one to three days, sometimes more, before a red rash appears in the same area. A zoster rash usually occurs on only one side of the body. A fever or headache also may develop.
The rash soon turns into groups of blisters, which generally last for two to three weeks. At first the blisters are clear, but then look yellow or bloody before they crust over (scab) and disappear. It is unusual to have pain without blisters, or blisters without pain. The pain is often severe enough for a physician to prescribe painkillers.
While zoster is most common on the trunk and buttocks, it can appear anywhere the nerves have been affected, including the face, arms, or legs. Blisters on the tip of the nose signal possible eye involvement. Great care is needed if the blisters involve the eye because permanent eye damage can result.
DIAGNOSIS OF HERPES ZOSTER
To diagnose herpes zoster, a dermatologist looks at the appearance of the skin and asks if the patient has experienced pain before the rash developed. To confirm the diagnosis, a dermatologist may scrape skin cells from a blister onto a glass slide for examination under a microscope. Also, the blister fluid containing the virus can be sent to a laboratory for special testing.
TREATMENT OF HERPES ZOSTER
Zoster usually clears on its own in a few weeks and seldom recurs. While zoster is clearing, pain relievers can help ease the discomfort, and cool compresses may provide soothing relief. When diagnosed early (within 72 hours), oral anti-viral medication can be prescribed. This medication is often prescribed when the zoster is severe or affects an eye. Patients who have decreased immunity also are routinely prescribed an anti-viral medication. In addition to treating the zoster, an anti-viral medication can prevent post-herpetic neuralgia (pain, numbness, itching, and tingling that last long after the rash clears). The earlier treatment is started, the better.
To reduce swelling and pain, a corticosteroid may be prescribed along with the anti-viral medication. A corticosteroid also can help alleviate inflammation when a severe infection develops such as in an eye. Nerve blocks can help control pain. If a patient develops post-herpetic neuralgia (pain, numbness, itching, and tingling that lasts long after the rash clears), it may be treated with pain relievers. Oral medications, anti-depressants, anti-seizure and antineuralgia medicines also may be of some benefit. Patients with zoster rarely require hospitalization.
COMPLICATIONS OF HERPES ZOSTER
Probably the most common problem of herpes zoster is post-herpetic neuralgia, which is described above. The pain, numbness, itching, and tingling can last for months or even years. It is more common in older people.
A bacterial infection can develop in the blisters, which can delay healing. Persistent pain and redness warn of an infection. If either occurs, return to the dermatologist. Antibiotic treatment may be needed. An infection involving zoster lesions can lead to scarring if not appropriately treated in a timely manner.
Zoster in the eye that is not promptly treated can lead to complications such as glaucoma, scarring, and blindness.
VACCINATION AGAINST HERPES ZOSTER
A vaccine has been approved by the U.S. Food and Drug Administration (FDA) for persons aged 60 years and older who have never had zoster. In one study, this immunization decreased the incidence of shingles by more than 50 percent. This vaccine has not been studied in persons with a history of shingles, and it should not be given to people who have decreased immunity (e.g., HIV, active cancer, taking drugs that decrease the immune response, etc.).
Another vaccine has been approved to prevent chicken pox. Typically given to children, the vaccine also may be given to some adults who have not had chicken pox.