Shingles is an infection of a nerve and the surrounding skin surface that is supplied by the nerve, caused by the varicella-zoster virus. This is the same virus that causes chickenpox and anyone who has recovered from chickenpox, child or adult can get shingles.1
There are an estimated 1 million cases of shingles each year in the US, with 1 in 3 people developing shingles (also known as herpes zoster) during their lifetime.3
Shingles is characterized by a painful, blistering skin rash that typically lasts 2 to 4 weeks. Even after the rash has dissipated, some people continue to experience nerve pain for months, or even years. This condition is known as postherpetic neuralgia or PHN, and is the most common complication of shingles. The risk of shingles and PHN increases as a person gets older.
Contents of this article:
You will also see introductions at the end of some sections to any recent developments that have been covered by MNT's news stories. Also look out for links to information about related conditions.
Fast facts on shingles
- Around 1 in 3 people may develop shingles during their lifetime.
- Each year in the US, there are an estimated 1 million cases of shingles.2
- Over half of all shingles cases occur in people over the age of 60, with the burden of illness twice as high in people over 70, compared to people aged 60-69 years old.4,18
- Shingles in caused by the same virus that causes chickenpox - varicella-zoster virus.
- Shingles is a painful infection of the nerve supplying an area of skin and is accompanied by a localised skin rash.
- Older people and those with a weakened immune system are at greater risk for developing shingles.
- Symptoms that accompany shingles may include headache, fever, nausea and body aches.
- Shingles is often diagnosed by a doctor based on the appearance of the rash.
- Antiviral and pain medication can be used to treat shingles.
- Shingles can exhibit complications in some individuals; the most common is postherpetic neuralgia.
- For some individuals, a vaccine is available to reduce the likelihood of developing shingles.
What is shingles?
Shingles is caused by the varicella-zoster virus - the same virus that causes chickenpox. After recovery from chickenpox, the virus remains in the body and lies dormant in the central nervous system.
Varicella-zoster virus belongs to a group of viruses called herpes viruses, which is why shingles is also known as herpes zoster.5
All herpes viruses are able to hide in the nervous system, where they can remain latent for months or even years after initial infection. Nerves connect the central nervous system to the rest of the body and, given the right conditions, the herpes zoster virus can travel down nerve cell fibers to cause a renewed active infection.6
Varicella-zoster (shingles) virus belongs to a group of viruses called herpesviruses.
The blistering skin rash associated with shingles is usually isolated to one or more bands, called dermatomes, on one side of the trunk, around the waistline, or clustered on one side of the face.7 These dermatomes correspond to a specific sensory nerve that exits from the brain or spinal cord, which is why infection of a specific nerve causes isolated skin lesions rather than a body-wide rash and nerve pain.
The inactive virus may not cause problems for years, if ever. Shingles cannot develop as a secondary eruption if an earlier exposure to chickenpox has not occurred. Shingles is most common in people over the age of 50, about half of all cases occur in men and woman age 60 years and older. The risk of disease increases as a person gets older but the virus may reappear in people of all ages who have previously had chickenpox.4
Typically individuals will develop one episode of shingles in their lifetime. In some rare cases an individual may have a second or third episode.
The pain from shingles can be mild to severe and is characterized as a burning, shooting pain or itching, generally on one side of the body. The pain and the blistering skin rash do not usually cross over the midline of the body, which is one of the reasons shingles is fairly easy to diagnose compared to other diseases with dermatological manifestations.
The development of a blistering skin rash in this pattern indicates the reactivation of the dormant virus and its migration from the central nervous system to the skin, causing inflammation along the way. This pain can sometimes last for months after the rash has healed.
Most adults with the dormant virus never experience an outbreak of shingles, which is contingent upon something (as yet unknown) reactivating the virus.
What causes shingles?
In the majority of shingles cases there is no known trigger that causes the varicella-zoster virus to begin to multiply again. One suggestion is that shingles is an opportunistic condition that occurs when something compromises the immune system, alerting the virus to reactivate. Some possible triggers for shingles include:
- Ageing - shingles is 10 times more likely to occur in people over 60 than in children under 108
- Diseases - diseases including certain cancers, namely leukemia and lymphoma, and HIV or AIDS compromise the immune system. People with HIV are 25 times more likely to get shingles than the rest of the population9
- Cancer treatments - chemotherapy and radiation therapy can lower resistance to disease
- Stress or trauma - psychological and emotional stressors
- Medications - immunosuppressive drugs to prevent transplanted organ rejection and prolonged steroid use, such as prednisone. After a transplant 25-45% of people may develop shingles10,11
- Children - youngsters whose mothers had chickenpox late in pregnancy or had chickenpox in infancy themselves.
Recent developments on shingles causes from MNT news
A new study claims to have ruled out a link between childhood vaccination against varicella (chickenpox) and the increased incidence of herpes zoster (shingles) in adults, according to an article published in the Annals of Internal Medicine.
A recent report published in the Archives of Dermatology finds that people who have herpes zoster - commonly known as shingles - are more likely to have family members who also have had the condition.
A new study from the Mayo Clinic in Rochester, MN, finds that having asthma may increase the risk of developing shingles.
On the next page we look at the signs and symptoms of shingles, tests and diagnosis plus prevention and treatments for shingles.