Shingles (Herpes Zoster) Infection
Shingles (Herpes Zoster) Infection
Shingles is a disease that arises when the varicella-zoster virus (VZV), which causes chickenpox when it initially infects a human, reactivates after lying dormant in nerve cells. Shingles develops first as localized pain after which a rash, composed of fluid-filled blisters, forms. Fever, headache, chills, and a general feeling of sickness often accompany the pain. The rash develops within a few days and it may take several weeks for the blisters to break open and crust over. A person is infectious until the rash crusts over. Some cases of shingles result in serious complications, the most common being post-herpetic neuralgia, a type of nerve pain.
Treatment for shingles involves oral administration of an antiviral treatment. In addition, the symptoms and any complications also are treated. Treatment for postherpetic neuralgia is aimed primarily at controlling the pain.
Shingles is a worldwide disease, but is most common in older adults, usually those aged 50 year old or older. Immunocompromised people are also at a greater risk of developing shingles. Prevention is achieved by preventing exposure of non-immune individuals to the fluid from rash blisters. In addition, a vaccine has been developed that is aimed at preventing shingles in patients 60 years old and older.
WORDS TO KNOW
CHICKENPOX: Chickenpox (also called varicella disease and sometimes spelled chicken pox) is a common and extremely infectious childhood disease that can also affect adults. It produces an itchy, blistery rash that typically lasts about a week and is sometimes accompanied by a fever.
IMMUNOCOMPROMISED: A reduction of the ability of the immune system to recognize and respond to the presence of foreign material.
POSTHERPETIC NEURALGIA: Neuralgia is pain arising in a nerve that is not the result of any injury. Postherpetic neuralgia is neuralgia experienced after infection with a herpesvirus, namely Herpes simplex or Herpes zoster.
VARICELLA-ZOSTER VIRUS (VZV): Varicella zoster virus is a member of the alpha herpes virus group and is the cause of both chickenpox (also known as varicella) and shingles (herpes zoster).
Shingles, which is also known as herpes zoster, is caused by a virus known as varicella-zoster virus (VZV). This virus also causes chickenpox. Shingles arises in people who have already had chickenpox, since the virus remains in the body.
Usually, VZV remains dormant in the body. It settles in nerve roots, and when activated, causes the development of shingles. Shingles is characterized by the development of pain, itching, or tingling in a region on the body where a rash will develop a few days later. This pain is often accompanied by fever, headache, chills, or an upset stomach, making patients feel unwell. The rash develops blisters filled with fluid. These blisters break open and crust over. Infection normally lasts for four to five weeks, and, in most individuals, the skin heals and recovery is complete.
Some cases of shingles develop serious complications. Skin may be damaged due to scratching of the rash, and some cases of skin damage result in scarring. Deafness and blindness also can occur when the virus spreads to nerves within the ear or eye regions. This may be temporary, but in some cases is permanent. Brain inflammation (encephalitis) and death may also occur in rare cases. More commonly, pain may occur following recovery from the rash.
Approximately 20% of people with shingles develop this pain, known as post-herpetic neuralgia. The pain is often severe and most likely is caused by nerve damage.
The varicella-zoster virus is transmitted when humans come in contact with airborne respiratory droplets or with fluid from rash blisters. When a person is first infected with this virus, they develop chickenpox. Once a person has contracted this virus, they retain it, and shingles develops when the virus reactivates. Exposure to fluid from shingles blisters does not cause people to become infected with shingles, but it can cause a person with no prior infection to contract chickenpox.
Varicella-zoster virus occurs worldwide and causes the development of both chickenpox and shingles. Within the United States, the Centers for Disease Control and Prevention (CDC) reports an estimated one million cases of shingles annually. Anyone who has had chickenpox, and thus retains VZV, can potentially develop shingles. However, the majority of shingles cases occur in people older than 50 years of age. While children and adults under 50 do develop shingles, the risk of developing shingles increases with age.
Shingles is also more likely to develop in people who are immunocompromised. People with medical conditions, such as cancer or HIV, or those who have received organ transplants, have a compromised immune system that is less able to fight off infections. Therefore, these individuals are more likely to develop shingles.
While shingles cannot be spread from one person to another, people who have not previously been infected by VZV can contract the virus if they come in contact with infectious fluid from shingles blisters. However, this will result in chickenpox, not shingles.
While the majority of shingles patients recover fully after an infection, the CDC reports a fifth of U.S. patients suffer from post-herpetic neuralgia. This amounts to 200,000 people who develop this condition annually.
Treatment is available for shingles and recovery is more likely the sooner treatment is administered. Shingles is treated using antiviral medications that are administered orally. These include acyclovir, famciclovir, and valacyclovir. Treatment does not cure the viral disease. Instead, it acts to hinder the progression of the disease throughout the nerves.
To treat the symptoms of shingles, in particular, the pain from the rash, pain-relieving medications, such as ibuprofen, naproxen, indomethacin, and nonsteroidal anti-flammatory drugs, are administered. For more intense pain, stronger analgesics, such as codeine or oxycodone, may be prescribed.
Treatment for post-herpetic neuralgia varies. The treatments tend to focus on treating the pain. Some treatments include: patches that release the pain-relieving medication lidocaine directly into the affected area; analgesics, which have sedating properties; opioids, which control pain; and antidepressants, which help patients tolerate severe pain. Some patients also receive electrical nerve stimulation or have the affected nerve cells blocked. However, the pain experienced often differs from patient to patient, and treatments that work for one patient do not necessarily work for another.
The spread of VZV from shingles patients to previously non-infected peoplecan be prevented by covering the rash, avoiding touching the rash, and washing hands often to prevent contaminating items with fluid from the rash. Once the rash crusts over, the virus is no longer contagious.
A vaccine has been developed that causes people to develop immunity to VZV. This has been found to decrease the number of people developing chickenpox, and is thought to lessen the risk of the virus remaining dormant and possibly reactivating as shingles. A new vaccine, Zostavax, was developed in 2006. This vaccine prevents shingles and, in 2006, the vaccine was approved for use in patients 60 years old and over.
Shingles usually affects older people and, in 20% of cases, the patient develops post-herpetic neuralgia. Postherpetic neuralgia is nerve pain that lasts for three months or more. The pain can vary from mild to severe, and patients may experience burning, stabbing, or gnawing sensations. This side effect of the varicella-zoster virus is a serious issue for a number of reasons. The pain experienced by persons with shingles can often be persistent and debilitating. Furthermore, the treatments used for nerve pain tend to work for some people, while having no effect for other people, making pain management difficult. The number of people in the United States suffering from post-herpetic neuralgia is significant and while some may be relieved of the pain in a few months, many suffer severe pain for years following recovery from shingles.
Shingles can also be a dangerous disease when it infects immunocompromised persons. People with medical conditions, such as cancer or HIV, or those who have received organ transplants, have weakened immune systems and they are less capable of fighting off the disease. Therefore, more serious complications such as post-herpetic neuralgia, meningitis, and even death, are more likely in these persons if they contract shingles. Furthermore, vaccination is not a viable option, since even small doses of the virus may cause complications for these people. Therefore, avoidance of the virus, or rapid treatment, is vital for patients who are immunocompromised in order to prevent serious complications.
IN CONTEXT: PERSONAL AND SOCIAL RESPONSIBILITY
The National Immunization Program (NIP) at Centers for Disease Control and Prevention (CDC) states that “Shingles cannot be passed from one person to another. However, the virus that causes shingles, VZV, can be spread from a person with active shingles to a person who has never had chickenpox through direct contact with the rash. The person exposed would develop chickenpox, not shingles. The virus is not spread through sneezing, coughing or casual contact. A person with shingles can spread the disease when the rash is in the blister-phase. Once the rash has developed crusts, the person is no longer contagious. A person is not infectious before blisters appear or with post-herpetic neuralgia (pain after the rash is gone).”
With regard to what can be done to prevent the spread of shingles, the CDC states that “the risk of spreading shingles is low if the rash is covered. People with shingles should keep the rash covered, not touch or scratch the rash, and wash their hands often to prevent the spread of VZV. Once the rash has developed crusts, the person is no longer contagious.”
SOURCE: Centers for Disease Control and Prevention, National Immunization Program (NIP)
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"Shingles (Herpes Zoster) Infection." Infectious Diseases: In Context. . Encyclopedia.com. (April 18, 2019). https://www.encyclopedia.com/media/educational-magazines/shingles-herpes-zoster-infection
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