Shingles, or herpes zoster, is a painful rash of blisters that develops due to the virus that causes chickenpox.
A primary, that is, first-time, infection with a virus called the varicella-zoster virus causes chickenpox. After someone recovers from chickenpox, the virus remains inactive, or dormant, in the nerve sheaths. The infection can reactivate for various reasons later in life, causing a painful condition known as zoster, or "shingles".
Shingles symptoms are usually limited to a small area of the body. This area is usually a small strip of skin on one side of the chest or abdomen. In some cases, the face, including the eye, can be involved.
The first symptoms are usually related to sensation. People may experience pain, numbness, tingling, or itching. Pain usually occurs at some point, and can be quite severe. This is usually followed by the development of groups of blisters. The areas around the blisters are often quite painful. The pain can be severe and last for weeks. Pain is usually much less severe in children.
The cause of this condition is a reactivation of the chickenpox virus. Most people in the US are infected with this virus. Weakness of the immune system may increase the risk of developing shingles. In people with weakened immune systems, infection can be very serious. In these people, the virus can spread all over the body, causing infection in the liver, lungs, and brain.
Primary varicella-zoster infection, or chickenpox, can be prevented. If chickenpox is prevented, shingles will not occur. Varicella vaccine is now routinely recommended for children, and for adults who have not had chickenpox. The vaccine is given in combination with measles, mumps, and rubella vaccines as MMRV.
More recently, a formulation of vaccine that will reduce the risk of shingles in an individual who previously had chickenpox, has been approved for use, and recommended for individuals 60 years and older.
People with weak immune systems that have not had chickenpox may be given varicella zoster immune globulin (VZIG) if they are exposed to chickenpox, to reduce their risk of catching the disease.
Usually the diagnosis of varicella-zoster is made by the history of the illness and a physical exam. The virus can be recovered from the blisters and identified with special tests. Blood tests can also be used to make the diagnosis in some cases if needed.
In most cases, shingles goes away in a few weeks or so and causes no long-term effects. However, some cases result in serious long-term effects. Eye involvement may lead to blindness. Some people have chronic pain in the area of the blisters that persists for months or even years.
Paralysis in the part of the body that had blisters occurs very rarely. In people with a weak immune system, the virus may cause a serious infection in the body. This may result in liver, brain, or lung damage, and possibly even death.
The virus can be spread to others if they are exposed to the fluid in the blisters. If a person who has not received the varicella vaccine or had chickenpox before is exposed to someone with shingles, he or she may develop chickenpox, though a shingles case does not spread virus as easily as does a case of chickenpox.
Oral antiviral drugs such as acyclovir (i.e., Zovirax), valacyclovir (i.e., Valtrex), or famciclovir (i.e., Famvir) can be used to treat shingles. Drugs for pain may also be needed. Eye infection usually requires the use of special eye drops to reduce inflammation.
Headaches and nausea may occur with the oral drugs used to treat shingles. People with severe infections may need acyclovir injected directly into the veins, which may cause kidney problems. Drugs for pain may cause stomach upset, allergic reactions or sleepiness. Exact side effects depend on the drug used. Eye drops can cause irritation and allergic reactions in the eyes.
In most cases, the shingles go away and people can return to normal activities. Pain may remain at the site of the healed blisters. Drugs for pain may be needed. People with eye infection may require long-term eye care from an eye doctor.
Most cases are monitored by the affected person at home. In severe infections, a person may need to be monitored in the hospital. Further monitoring in this setting would depend on the areas of the body that are affected by the infection. Those with eye infections usually need repeated eye examinations until the infection resolves.