What is shingles?
Shingles is a viral infection caused by the varicella-zoster virus (also known as VZV, herpes zoster). Shingles usually causes a single strip or patch of painful blisters that wrap around either the left or right side of the patient's torso or extremities, although it may occur on the face. Shingles results from the activation of the chickenpox virus already present, but inactive (dormant), in nerve tissues. The virus remains dormant in spinal nerves (dorsal root ganglia) usually after the person has had chickenpox as a child. The virus can remain dormant in the nerve tissues for many years and then can become activated along an infected nerve or group of nerves, usually in adults (50-60 years and older). However, about 20%-25% of shingles infections occur in individuals less than 20 years old. The shingles virus can even damage the unborn baby and newborns if their mothers develop chickenpox during pregnancy.
Is shingles contagious?
Individuals who never have had chickenpox and have not received the vaccine for chickenpox are susceptible to shingles virus infection. Consequently, shingles disease is contagious for chickenpox by transmission of the varicella-zoster virus (VZV) to these individuals. However, the shingles rash is not contagious in that a rash from one individual is unable to spread to another individual so the disease, shingles itself, is not directly contagious. Nevertheless, the disease of shingles can pass the virus from its active rash blisters directly to another individual (an adult, child, or baby) who can become infected with the varicella-zoster virus if the individual is not immune to VZV and develop chickenpox. The chickenpox infection can cause shingles in some individuals later in their life. Shingles, in this manner, may be considered to be indirectly contagious. Moreover, because varicella-zoster virus infection is commonly contagious in the form of chickenpox, and this infection can eventually lead to shingles development in some patients, it is fair for some researchers to say that shingles is indirectly contagious by the spread of chickenpox.
When is shingles contagious?
A rash will begin to appear after a few days of symptoms such as
- skin tingling,
- burning, and/or
- numbness, usually on only one side of the body.
During the appearance of this rash and subsequent blister formation, the patient begins to shed the virus from the skin lesions and is contagious.
Shingles has two stages:
- a prodromal stage and active stage; and
- the prodromal stage or period consists of symptoms without the rash while the active stage or period begins when the rash starts.
How long is shingles contagious?
Classic symptoms of shingles are painful blisters in a band along a nerve distribution on one side of the body. These blisters usually break open and ooze fluid. This may last about five to seven days. The pain in the area of the rash can be intense as the nerve is irritated. The individual is contagious and can spread the virus when blisters are forming and until all of the blisters have crusted over. The rash may heal in about two to four weeks, and some skin areas may scar.
Can shingles spread by touch or by saliva?
The varicella-zoster virus (VZV) that is shed from the shingles lesions is very contagious to those people who have never had exposure to chickenpox or the chickenpox vaccine who then touch the blisters. Although shingles is not routinely thought of as being transmitted or spread by intercourse or sexual contact, individuals should be aware that during these activities if they touch other individuals with shingles who are still shedding the virus, the virus may be spread to the uninfected individual. This second individual, if not immune to VZV, would then have the virus in them and could develop chickenpox and perhaps shingles in the future.
Theoretically, it may be possible to spread VZV to other individuals during a zoster outbreak because VZV has been reportedly detected in saliva and nasal secretions in individuals with chickenpox and/or shingles. However, there is little or no data about the frequency of secretion transmission. Such spread of VZV to others is considered to occur rarely.
When should people seek medical care for shingles?
If people develop pain and/or a rash in a band on one side of the body or face, they should seek medical care is as soon as possible as treatments may reduce the pain and any possible further nerve or eye problems. If the rash occurs near the nose or eyes, they should seek emergency medical care. Individuals with a medical problem or taking medication that decreases their immune response (such as pregnancy, cancer, chemotherapy, HIV) should seek help immediately if they suspect they may be developing shingles. Children should be vaccinated against chickenpox and older individuals (50-60 years old) should discuss the shingles vaccine (Zostavax, Shingrix) with their doctors to reduce the risk of developing shingles.
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United States. Centers for Disease Control and Prevention. "Chickenpox (Varicella)." Dec. 31, 2018. <http://www.cdc.gov/chickenpox/about/transmission.html>.
United States. Centers for Disease Control and Prevention. "Shingles (Herpes Zoster)." Dec. 31, 2018. <http://www.cdc.gov/shingles/vaccination.html>.
United States. New York State Department of Health. "Chickenpox (Varicella Zoster Infection)." Jan. 2014. <https://www.health.ny.gov/diseases/communicable/chickenpox/fact_sheet.htm>.