A person must have had chicken pox in the past to develop shingles. After chicken pox, which usually occurs in childhood, the virus can remain in the body for the rest of a person’s life. Usually it is dormant or inactive in certain nerve cells of the body, causing no signs or symptoms. Occasionally, circumstances that are not fully understood lead to a temporary decrease in the body’s resistance to the virus. This allows the virus to start multiplying along nerve fibers under the surface of the skin, causing little fluid-filled blisters in a rash called shingles. These blisters contain newly produced virus.
The first symptom is burning pain or tingling and sensitivity in an area of skin supplied by the infected nerve fibers. Any part of the body supplied by these nerve fibers (dermatome) can be affected. Pain and tingling may appear three to four days before a red rash appears. A group of blisters very similar to chicken pox lesions then forms along the original red area. Generally blisters last two to three weeks, during which time they fill with pus, crust over, and then begin to disappear. Pain may be severe and last several months or longer. Some people only experience pain and never get the rash. Increased sensitivity of the skin may also last several months.
Shingles generally only affects one side of the body. Blisters commonly appear on the face or trunk, including the genitals and buttocks. If the blisters begin to close to the eye, immediate attention from an eye specialist is needed to prevent permanent damage. Lesions can also affect the mouth, tongue, or ear canal.
Shingles affect roughly 10 to 20 per cent of people at some point in their lives. The disease is most often seen in the elderly. However, it can happen at any age providing there has been a prior episode of chicken pox. It affects both sexes and all races equally. Although shingles often affects otherwise healthy people, anyone with a weakened immune system is more at risk. This includes those with cancers such as leukemia or lymphoma, those undergoing chemotherapy or radiation treatment for cancer or people with suppressed immune systems, either from medications to prevent transplant rejection or from disease such as AIDS.
Exposure to someone with shingles or chicken pox will not cause shingles but may cause chicken pox in someone who has not already had it. As mentioned, the virus is in the blisters and can be passed on to someone else until the blisters crust over. Only two per cent of healthy people ever have a second attack. Those with weakened immune systems may suffer repeated episodes.
The most troublesome complication of shingles is the associated pain. Pain occurring after shingles and lasting more than a month, is called “postherpetic neuralgia” (PHN). PHN is not common in younger people but affects at least 50 per cent of those over age 50. It can be severe enough to make it hard to carry out normal day-to-day activities.
More serious complications of shingles are not common in otherwise healthy people. They are more likely to affect those with weakened immune systems. Shingles can progress to involve the central nervous system, causing a form of meningitis. Shingles can also affect other parts of the body such as the lungs and liver. Infections of the eye can lead to visual damage or even blindness.
Shingles treatment aims to relieve pain, get rid of the rash, speed up recovery, prevent a secondary infection and prevent or minimize PHN. Whenever possible, treatment with antivirals should begin within 72 hours of the first sign of the shingles rash. This helps clear up the rash and may reduce the risk of PHN. Acyclovir, famcyclovir and valcyclovir are examples of antiviral drugs.
Pain from shingles is not always helped by standard painkillers. A number of other approaches have been tried, though none have proven totally effective. Researchers are still looking for more ways to treat the pain of shingles. Anti-inflammatory drugs may be given in combination with pain medications. Tricyclic anti-depressants help almost half of people with PHN. Relief may also come from anticonvulsant medications used to treat epilepsy. Capsaicin, a cream made from the seeds of hot chili peppers, sometimes helps those who develop excessively sensitive skin from shingles. Aspirin™ cream and Lidocaine™ cream may help. TENS (transcutaneous electrical nerve stimulation) has also been used to reduce pain. Other approaches include local injection of steroids, nerve blocks and nerve surgery.
Those with weakened immune systems are more threatened by shingles. In these cases, high intravenous doses of antiviral drugs such as acyclovir have been used with considerable success. Varicella immune globulin may also provide protection.
Two vaccines may help prevent shingles – the chicken pox (varicella) and the shingles (varicella-zoster) vaccines. The chicken pox vaccine has been available in Canada since 1998 and the shingles vaccine came onto the market in 2009. The chicken pox vaccine is included as part of routine childhood immunization in Canada. It is also recommended for adults who have never had chickenpox. While the vaccine does not guarantee prevention of chickenpox or shingles, it can reduce the chances of complications and severe disease. The vaccine is very safe and side effects are mild.
The vaccine against shingles is used to prevent herpes zoster in adults over age 60 who have had chicken pox, whether or not they had shingles. You may still get shingles after vaccination, but chances are it will be less severe. The risk of PHN is also reduced.
The Zostavax™ vaccine reduces the risk of shingles by 50 per cent and PHN by 67 per cent. It is most effective in people aged 60 to 69. The vaccine is not used to treat shingles or PHN.
The Public Health Agency of Canada recommends the vaccine for anyone* over age 60. Talk to your doctor or pharmacist about your risk of shingles and the benefits of the vaccine. A doctor’s prescription is necessary to receive the vaccine which is available at many pharmacies (and by appointment at most Canada Safeway Pharmacy stores).
* Regardless of age, some people should not be vaccinated: