Herpes Zoster Infection
Written by Ada’s Medical Knowledge Team
What is herpes zoster infection?
Herpes zoster infection, often known as shingles, is a common viral infection caused by reactivation of the varicella zoster virus. The varicella zoster virus is also known as herpes zoster and is a member of the human herpesvirus family. Around one in three people in the United States will develop shingles in their lives, with 1 million cases in the country each year. 1 All people that develop shingles will have had chickenpox at some point in their lives, usually during childhood.
The the varicella zoster virus remains dormant in the body after a person has had chickenpox. After chickenpox, which is the acute form of varicella zoster infection, the virus lies dormant in nerves, and it can reactivate years later and cause new symptoms. 2
Herpes zoster infection is more likely to affect older people and people with a weak immune system. It causes a burning pain, followed by a painful blistering rash, which tends to only affect one area of the body. If you think that you might have shingles, you can try using the Ada app to find out more about your symptoms.
Shingles is treated with antiviral medications.** The rash will usually begin to get better within two weeks, and although most people recover well, some may be left with persistent pain in the affected area. Effective pain management from the early stages is therefore very important. Some complications of shingles, for example herpes zoster ophthalmicus, can lead to permanent problems with eyesight.
People with shingles should avoid contact with people who have not been vaccinated against chickenpox and people who have a weakened immune system.
Symptoms of herpes zoster infection
The first sign of herpes zoster infection is often a painful sensation in one area of the body. The pain is commonly described as: 3 4
The most commonly known symptom of shingles is the rash. Where the rash appears will depend on what part of the body the herpes zoster virus has been dormant in. The rash appears on the dermatome associated with the affected nerve.
Good to know: A dermatome is the area of skin supplied by a particular nerve. The varicella zoster virus lies dormant in the cranial and spinal nerves. When the virus is reactivated, it travels along the affected nerves to the area of the skin served by those nerves, where it causes a distinctive, stripe-like rash. 5
The rash is most common on the chest, back, shoulders or face. Pain and the accompanying rash can occur anywhere on the body, depending on which nerve is affected by the infection.
Several symptoms may appear before the rash develops. These are known as prodromal symptoms and include: 5 6
- Burning sensations or discomfort when the skin is touched
- Flu-like symptoms such as fever, malaise and fatigue
- Upset stomach
Between one and five days after the pain begins, a rash will develop in the same area: 2 3 4
- The rash is vesicular; vesicles are small, blister-like sacs that appear on the surface of the skin
- The skin around the vesicular rash becomes red
- The rash is generally confined to one area of the body in a stripe-like pattern; usually one side of the body or, in some cases, the face. In immunosuppressed people the rash may be more widespread
- The rash blisters burst and scab over, usually seven to 10 days after first appearing
- The rash generally goes away after two to four weeks
About one in every ten people with shingles will experience the onset of pain and the rash simultaneously.
Good to know: If someone has a healthy immune system, they are said to be immunocompetent. If they have a weak or damaged immune system, they are said to be immunocompromised or immunosuppressed.
Most people will only experience shingles once, though less than 4 percent will have another episode. 2
If you are concerned that you might have shingles, you can try using the Ada app for a free assessment.
Read more about Signs of Shingles »
Zoster sine herpete: shingles without a rash
Occasionally, shingles can occur without a rash of blisters: this is known as <em>zoster sine herpete.</em> In this form of the condition, the affected person will experience all the usual prodromal symptoms, such as fever and itching or burning, but does not then develop blisters. 7 They may also develop a raised red area on the area of skin where they feel the itching or burning.
People with this condition experience pain and discomfort in the same dermatomal distribution as normal shingles, but the skin of the affected area may be red. <em>Zoster sine herpete</em> can be diagnosed using tests rather than physical examination. 8
Causes of herpes zoster infection
People at risk of developing shingles are those who have had chickenpox in the past. Herpes zoster infection occurs years, often decades, after a person has been infected with the varicella zoster virus that causes chickenpox.
The virus remains dormant in the body in the ganglia of the sensory cranial nerves and spinal dorsal root (see FAQs). If a person’s immunity to varicella zoster weakens over time, either due to age or if a person is immunosuppressed, the virus can reactivate. This reactivation is called herpes zoster infection, or shingles. 5
Conditions and situations that can suppress the immune system and make someone more at risk of developing shingles include: 9
- Receiving chemotherapy
- Having the spleen removed ‒ for example, due to damage from injury or infection
- Hypogammaglobulinemia, a condition where the body does not make enough antibodies
If you have a condition which affects your general health, and are experiencing symptoms that may be those of shingles, you can check your symptoms using the free Ada app at any time.
Diagnosis of herpes zoster infection
A diagnosis can usually be made based on the symptoms and the appearance of the rash. If there is uncertainty, the diagnosis can be confirmed with blood tests or by taking a sample of fluid from a blister and testing for the virus.
Complications of herpes zoster infection
Shingles can cause complications if it affects the eye and the ear. It can also cause long-lasting pain even after the rash has gone.
Good to know: People who are older than 60 years of age are particularly vulnerable to complications of shingles and should visit a doctor as soon as they develop symptoms. 10
Rarely, shingles can lead to complications such as pneumonia, encephalitis or a secondary bacterial infection of the skin. 10
Herpes zoster ophthalmicus
Herpes zoster ophthalmicus, or ophthalmic shingles, is a variant of shingles where the virus affects the ophthalmic nerve and eye, causing pain and inflammation in the eye and face. If not treated quickly, it has the potential to cause permanent vision problems, including: 11 12 13
- Scarring of the tissues of the eye
- Retinal necrosis, a condition in which the retina becomes inflamed
- Iritis or uveitis, inflammation of the tissues of the eye
Secondary bacterial infections of the eye can also occur if the affected eye becomes dry and sustains small scratches as a result of the inflammation. Some people find that prescriptions gels, ointments or drops that lubricate the eye are useful in relieving discomfort caused by dry eyes. 13
Read more about Herpes Zoster Ophthalmicus »
Herpes zoster oticus
Herpes zoster oticus, or Ramsay Hunt syndrome, occurs when the herpes zoster virus affects facial nerves. In this way it is like herpes zoster opthalmicus, but in this case the pain affects the ear. HZO is a rare form of shingles that causes pain deep within the ear and facial palsy as well as the rash. With treatment, most people will recover full use of facial nerves. 14
Treating herpes zoster oticus involves antiviral medications and pain management. (For more information, see the treatment section.)
Some people infected with herpes zoster will continue to feel pain in the affected areas of the body. Pain that persists for three months or longer is called postherpetic neuralgia (PHN). 2
Postherpetic neuralgia pain is caused by damage to nerves during the shingles infection. It is more common in older people, rising to 20 percent of people 80 years and older experiencing PHN after shingles. 5
Symptoms and effects of postherpetic neuralgia include:
- Sharp pain
- Intermittent or constant pain
- Allodynia, which is pain caused by light touches or the feel of clothing on skin
- Difficulty sleeping
The experience of living with PHN may bring on clinical depression.
Treatment of herpes zoster infection
Herpes zoster infection is usually treated with antiviral medication in people who are immunocompetent. These drugs helps shorten the duration and lessen the severity of shingles by easing the associated pain and promoting healing of the blisters. Medication should be taken as soon as possible after the rash appears. 15
Drugs often prescribed include: 16 17 18 19
- Acyclovir. Taken orally, acyclovir has been the traditional antiviral for use in shingles treatment. However, other drugs have been developed which can be taken less frequently and are better absorbed by the body.
- Famciclovir. Taken orally, famciclovir converts to the compound penciclovir which is effective against the varicella zoster virus.
- Valacyclovir. Taken orally, valacyclovir treats pain and itching and helps sores to heal while preventing new sores forming.
Common side-effects of these drugs can include: 17 18 19
- Nausea and vomiting
- Upset stomach
- Painful menstruation
Some doctors may prescribe steroid tablets to reduce swelling and itching, but this is not recommended in most cases. Anti-inflammatory medications, such as ibuprofen, or other analgesics, may also help to reduce the pain and swelling.
People with shingles should try to avoid scratching at the rash. Calamine lotion and wet compresses can help soothe the itching.
Treatment of herpes zoster infection in the immunosuppressed
People whose immune systems are compromised are more likely to experience complications from shingles, which can include: 20 21
- The rash spreading across the body
- Infection of the lesions, usually due to Staphylococcus aureus
- Encephalitis, inflammation of the brain
- Deafness caused by herpes zoster oticus
It is even more important to treat immunosuppressed people with antiviral drugs to limit complications, potentially requiring hospitalization to administer drugs intravenously. The antiviral drugs are the same as those given to immunocompetent people.
Treatment of postherpetic neuralgia
Early prescription of painkillers to people with herpes zoster infection is advised to try and prevent the development of postherpetic neuralgia. Types of painkillers prescribed may include:
- Paracetamol (acetaminophen)
Good to know: Codeine, tramadol, oxycodone and morphine are opioid painkillers and should only be used if ibuprofen and paracetamol alone prove ineffective.
If postherpetic neuralgia develops, it can also be treated with: 5
- Topical creams, such as lidocaine and capsaicin, to ease pain and allodynia in particular
- Antidepressants, such as tricyclics or selective serotonin (SSRIs) and norepinephrine reuptake inhibitors (SNRIs) to relieve pain and counter effects of clinical depression
- Anticonvulsants, such as pregabalin or gabapentin, to relieve neuropathic pain
Prevention of herpes zoster infection
People who have shingles should keep away from people who have not been vaccinated against chickenpox, especially newborns, pregnant people, and people who have a weak immune system.
People who need to be especially cautious around people with shingles include:
- Pregnant people who are not vaccinated against varicella zoster or who have not had chickenpox
- People with compromised immune systems as a result of organ transplants, leukemia, cancer or HIV
- People with compromised immune systems as a result of medication, such as steroids or chemotherapy
- Newborn babies
- Young, unvaccinated children
- The elderly, especially those with existing health conditions
Although shingles itself cannot be passed from person to person, the varicella zoster virus which causes chickenpox can be transmitted by contact with the fluid in the rash blisters. 22 If you or someone you care for have recently been around someone with shingles and are concerned that you or they may have contracted chickenpox, you can do a free symptom assessment using the [Ada app]9https://app.adjust.com/e8ex7r4?redirect_macos=https%3A%2F%2Fappstore.com%2Fadapersonalhealthcompanion).
Vaccination for herpes zoster infection
Vaccination against chickenpox (the varicella vaccination) and herpes zoster (a herpes zoster vaccination) can help to prevent and reduce the severity of some cases of shingles.
The Centers for Disease Control recommends that all healthy adults aged 50 and older should receive a shingles vaccine. This is especially recommended, because older adults are more at risk of developing complications from shingles.
Depending on the age of the person receiving the vaccine, it is between 89 and 97 percent effective at preventing shingles and postherpetic neuralgia. 23
FAQs for herpes zoster infection
Q: Is herpes zoster contagious?
A: Herpes zoster (shingles) itself is not contagious - this means that someone with shingles cannot give shingles to someone with whom they come into contact. However, it is possible for someone with shingles to pass on the varicella virus through contact with fluid from the rash blisters. If the person who contracts the virus is not vaccinated, they may then contract the virus and develop chickenpox.
Q: How long is someone with shingles contagious for?
A: The person with shingles is contagious until the rash develops crusts. 24
Q: Can children get shingles?
A: Yes: anyone who has had chickenpox can develop shingles, including children. However, this is rare. 25 Shingles is much more common among older adults than it is among children or young adults. 10
Q: What can someone with shingles do to avoid passing on the varicella virus to others?
A: Someone who has shingles should keep their hands clean, avoid scratching the rash and keep the rash covered, if possible. The shingles virus is not spread through coughing or sneezing, but it can be spread through direct contact with the rash. 25
Q: Who should avoid contact with someone who has an active shingles rash?
A: People who are at particular risk of shingles, and who should therefore avoid someone with shingles, include: 10 24 25
- People who have not had chickenpox and are not vaccinated against it
- People who are pregnant and have had neither chickenpox nor the vaccine against it
- People who have weakened immune systems due to medications such as steroids or organ-transplant drugs, or medical conditions such as cancer, HIV or leukemia. People undergoing chemotherapy should also avoid contact with someone affected by shingles.
- The elderly
- Unvaccinated children
- Newborns and very young infants
Q: What are the cranial sensory nerves and spinal nerves, and what role do they play in shingles infection?
A: The sensory cranial nerves are the nerves in the head which are responsible for sensations such as sight and smell. There are many pairs of spinal nerves along the vertebrae; each nerve has a dorsal root and an anterior root. The anterior root allows motor neurons to leave the spinal cord, while the dorsal root allow sensory neurons to enter the spinal cord. 26
A sensory neuron is a special type of nerve cell that transmits sensory stimuli such as touch, smell, sight and so on. In the skin, these are concerned primarily with touch. Neurons can be quite long, and their cell bodies collect in structures known as ganglia. 27 The dorsal and ventral roots merge together to form the spinal nerve. 28 The varicella zoster virus usually affects the dorsal roots of the spinal nerves and lies dormant in the ganglia.
Q: Can you get shingles more than once?
A: In most cases, a person only has shingles once. However, some people have shingles two or three times in their lifetime. 25
Q: What is the relationship between shingles and Guillain-Barre Syndrome?
A: Guillain-Barre Syndrome is a very rare complication of shingles. 29
Guillain-Barre Syndrome is a rare condition that usually occurs after a viral or bacterial infection. Although there is as yet no medical consensus about what causes Guillain-Barre Syndrome, it is known to be a condition in which the body’s immune system attacks its own peripheral nervous system. The severity of the condition can vary, ranging from temporary weakness to severe paralysis. However, most people with Guillain-Barre Syndrome do recover. It is somewhat more common among older people. 30
Q: What is the relationship between shingles and HIV?
A: People with HIV may experience shingles earlier in life than people without HIV and may need more aggressive antiviral treatment for varicella zoster than people without HIV.
Shingles can occur at any time after infection with HIV, which is associated with multiple recurrences of shingles, rather than the more usual one episode per lifetime. People with HIV are at somewhat higher risk of complications from shingles, including disseminated varicella zoster. 31
In most cases of varicella zoster infection, the rash is limited to one dermatome, but in people with compromised immune systems, the condition may become disseminated, meaning that it spreads throughout the body. 32 It can affect both the skin and the organs. Disseminated varicella zoster usually requires inpatient treatment in a hospital. 31
Q: Can shingles be treated with essential oils?
A: While many people claim that essential oils can be used to treat the rash for shingles, their effectiveness in this regard has not yet been conclusively proven by scientific study. 33 34 Always seek medical advice before using any natural remedies instead of, or in addition to, the recommended treatment plan. They may be unsuitable for certain people, and their use may be inadvisable in combination with particular medications.
Q: Can shingles be fatal?
A: Shingles is almost never fatal. However, in people who are physically debilitated, such as the very elderly or the very immunocompromised, shingles may make death more likely. 35
Q: Does shingles bleed?
A: While the rash associated with shingles may sometimes ooze small amounts of serum, it is not normal for it to produce pus or to bleed. If someone with shingles has a rash that is bleeding or is producing pus, they should seek medical attention as soon as possible. People with shingles should avoid scratching the rash, even though it is itchy, because they may cause bleeding and/or introduce bacteria to the broken skin, which may lead to a secondary infection.
Q: Can shingles leave scars?
A: Rarely, a severe shingles rash may lead to scarring or loss of pigment in affected skin. Scratching can cause the blisters to become inflamed and/or infected, which can lead to scarring.
Other names for herpes zoster infection
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