Infectious Diseases A to Z – Shingles (herpes zoster)

With this new column, Elite Healthcare will compile an index of various infectious diseases, with occasional highlights of emerging conditions. 

Shingles (herpes zoster)

General definition and information:

A viral infection that causes a painful, itchy rash of fluid-filled blisters, shingles is caused by the varicella-zoster virus (VZV), which also causes chickenpox. Shingles is a result of a reactivation of the VZV virus that occurs long after the chickenpox illness has run its course. The virus remains within the body in nerve tissue near the spinal cord and brain after recovery from chickenpox, and shingles can develop later in life even though most people who acquire chickenpox will be immune from ever getting pox again. Although a non-life-threatening condition, shingles can be very painful. According to the Centers for Disease Control and Prevention (CDC), nearly one in three people in the United States will develop shingles in their lifetime1 and there are an estimated 1 million cases of shingles per year in the U.S. Approximately 1-4% of patients who are diagnosed with shingles are hospitalized for complications, according to the CDC. Older adults and people with weakened or suppressed immune systems are more likely to be hospitalized. About 30% of those hospitalized have a weakened or suppressed immune system.

Children can also get shingles, however, the risk of shingles increases with age, according to the CDC. That said, not everyone who’s had chickenpox will develop shingles. Pain is most often the first symptom, and depending on the location of the pain, it can be difficult to diagnose because it may be mistaken for problems affecting the heart, lungs, or kidneys, according to the Mayo Clinic. Some people will experience shingles pain without ever developing the rash, but when the rash does develop, it is most commonly marked as a stripe of blisters that wraps around either the left or right side of the torso.2 The rash can also appear around an eye or on the neck or face. Multiple occurrences of shingles can appear in the same patient over his or her lifetime. The number of shingles cases is increasing among U.S. adults, according to the CDC. The reason for this increase is not fully understood, but one explanation offered by the CDC is that the increase may be related to fewer chickenpox cases among U.S. children due to widespread vaccination against chickenpox.

Causes & Modes of Transmission:

The true reason for shingles is unclear, although it may be due to lowered immunity to infections people grow older, according to the Mayo Clinic.2 Shingles is not transmissible from person to person, instead the VZV virus is spread from those with an active shingles condition to cause chickenpox in someone who has never had chickenpox or received the chickenpox vaccine. The virus is spread through direct contact with fluid from the rash blisters, however, people are not infectious before the blisters appear. Ultimately, the rash will develop crusts, and at that point, the person is no longer infectious, according to the CDC. Those who are living with medical conditions that keep the immune systems from working properly, such as certain cancers and HIV, and are receiving immunosuppressive drugs such as steroids, have a greater risk of getting shingles, according to the CDC. Another risk factor includes being older than 50. 

Prolonged complications due to shingles can include postherpetic neuralgia (PHN), pain that continues long after blisters have cleared when damaged nerve fibers send confused and exaggerated messages of pain from the skin to the brain;2 vision loss; neurological problems, including encephalitis, facial paralysis, or hearing and/or balance problems; and skin infections. A person’s risk of PHN also increases with age, as older adults are more likely to have PHN and to have longer lasting and more severe pain, according to the CDC, which reports that about 10-13% of people who get shingles will experience PHN, which occurs rarely among those who are younger than 40 years old. Shingles can be spread to people who have never had chickenpox or never received the chickenpox vaccine. 

Treatment Strategies:

Antiviral medicines including acyclovir, valacyclovir, and famciclovir are available options to treat shingles, shorten the length of the illness, and reduce the severity of the condition. Healthcare providers are urged by the CDC to have patients begin taking these medicines as soon as possible after the rash appears in order to provide the best chance of effective care. Analgesics may also be considered to help with pain relief, and wet compresses, calamine lotion, and colloidal oatmeal baths may help relieve itching. Anticonvulsants, tricyclic antidepressants, numbing agents, medications that contain narcotics, and an injection including corticosteroids and local anesthetics, are also treatment options. Patients can also be encouraged to take cool baths or using cool, wet compresses on the blisters to help relieve itching and pain. Stress will exacerbate the condition, according to the Mayo Clinic.

Prevention Parameters:

Vaccines can help reduce the risk of shingles, while early treatment can help shorten a shingles infection and lessen the chance of complications, according to the CDC. If the rash is covered, the risk of a person with shingles spreading the virus is low, according to the CDC. Patients who have been diagnosed with shingles should be instructed to cover their rash, avoid touching or scratching the rash, wash hands often, and avoid contact with people until the rash develops a crust. Patients should also be educated to avoid pregnant women who have never had chickenpox or the chickenpox vaccine; premature or low-birth-weight infants; and people with weakened immune systems. According to the CDC, 33.4% of adults 60 years and older reported receiving the Zostavax® vaccine in 2016, an increase from the 31% reported for 2015. CDC officials have said they will collect data on vaccination of adults who are ages 50 and older using Shingrix and will share this information when it is available.

References

  1. Shingles (herpes zoster). CDC. 2018. Accessed online: www.cdc.gov/shingles/about/overview.html
  2. Shingles. Mayo Clinic. 2018. Accessed online: www.mayoclinic.org/diseases-conditions/shingles/diagnosis-treatment/drc-20353060

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