Shingles and chickenpox (Varicella-zoster virus)
Chickenpox Vaccine Recommendations
The CDC recommends the following chickenpox (varicella) vaccination schedules for:
- Children ages 12 months - 12 years. All healthy children should receive their first chickenpox shot at age 12 - 15 months and a second shot at age 4 - 6 years (preferably before entering pre-kindergarten, kindergarten, or first grade).
- Adolescents and Adults ages 13 years and older. All healthy teenagers and adults who have never had chickenpox or the vaccine should receive 2 doses of the varicella vaccine, given 4 - 8 weeks apart.
Shingles Vaccine Recommendations
The CDC recommends the shingles (varicella-zoster) vaccine (Zostavax) for all adults age 60 years and older who have healthy immune systems. Zostavax is not approved for people younger than age 60.
Home Remedies for Chickenpox Relief
Chickenpox is uncomfortable and unpleasant, but most cases are relatively mild and resolve within 7 - 10 days. In otherwise healthy people who have a low risk for complications, home remedies can help provide relief from itching and fever.
- Oatmeal baths can help relieve itching.
- Calamine lotion can help dry out blisters and soothe skin.
- Acetaminophen (Tylenol) can help reduce fever.
- Antihistamines may relieve severe itching and aid sleep.
Most important, dont scratch! Scratching the blisters can cause scarring and lead to a secondary infection.
Shingles and chickenpox were once considered separate disorders. Researchers now know that they are both caused by a single virus of the herpes family, known as varicella-zoster virus (VZV). The word herpes is derived from the Greek word "herpein," which means "to creep," a reference to a characteristic pattern of skin eruptions. VZV is still referred to by separate terms:
- Varicella: The primary infection that causes chickenpox
- Herpes zoster: The reactivation of the virus that causes shingles
Varicella (Chickenpox). When patients with chickenpox cough or sneeze, they expel tiny droplets that carry the virus. If a person who has never had chickenpox or never been vaccinated inhales these particles, the virus enters the lungs. From here it passes into the bloodstream. When it is carried to the skin it produces the typical rash of chickenpox.
Herpes Zoster (Shingles). The varicella virus also travels to nerve cells called dorsal root ganglia. These are bundles of nerves that transmit sensory information from the skin to the brain. Here, the virus can hide from the immune system for years, often for a lifetime. This inactivity is called latency.
If the virus becomes active after being latent, it causes the disorder known as shingles. The virus in this later form is referred to as herpes zoster. The virus spreads in the ganglion and to the nerves connecting to it. Nerves most often affected are those in the face or the trunk. The virus can also spread to the spinal cord and into the bloodstream.
It is not clear why the varicella virus reactivates in some people but not in others. In many cases, the immune system has become impaired or suppressed from certain conditions such as AIDS, other immunodeficient diseases, or certain cancers or drugs that suppress the immune system. Aging itself increases the risk for shingles.
Other Herpes Viruses
The varicella-zoster virus belongs to a group of herpes viruses that includes eight human viruses (it also includes animal viruses). Herpes viruses are similar in shape and size and reproduce within the structure of a cell. The particular cell depends upon the specific virus. Human herpes viruses include herpes simplex virus 1 (HSV-1), which causes cold sores, and herpes simplex virus 2 (HSV-2), which causes genital herpes. Cytomegalovirus (CMV), which causes mononucleosis and retinitis, and Epstein-Barre Virus (EBV), another cause of mononucleosis, are also human herpes viruses.
All herpes viruses share some common properties, including a pattern of active symptoms followed by latent inactive periods that can last for months, years, or even a lifetime. [For more information, see In-Depth Report #52: Herpes simplex.]
The varicella-zoster virus is responsible for both chickenpox and herpes zoster, but its method of infection is different in both diseases.
- Both the active varicella and zoster form of the virus can cause chickenpox.
- The shingles virus in its latent (inactive) form is never contagious.
Catching Chickenpox. Most people get chickenpox from exposure to other people with chickenpox. It is most often spread through sneezing, coughing, and breathing. It is so contagious that few nonimmunized people escape this common disease when they are exposed to someone else with the disease.
People can also catch chickenpox from direct exposure to a shingles rash if they have not been immunized by vaccination or a previous bout of chickenpox. In such cases, transmission happens during the active phase when blisters have erupted but not formed dry crusts. Herpes zoster spreads only from the rash. A person with shingles cannot transmit the virus by breathing or coughing.
Developing Shingles. Shingles itself can develop only from a reactivation of the varicella-zoster virus in a person who has previously had chickenpox. In other words, shingles itself is never transmitted from one person to another either in the air or through direct exposure to the blisters.
Risk Factors for Chickenpox (Varicella)
Between 75 - 90% of chickenpox cases occur in children under 10 years of age. Before the introduction of the vaccine, about 4 million cases of chickenpox were reported in the U.S. each year. Since a varicella vaccine became available in the U.S. in 1995, however, the incidence of disease and hospitalizations due to chickenpox has declined by nearly 90%.
The disease usually occurs in late winter and early spring months. It can also be transmitted from direct contact with the open sores. (Clothing, bedding, and other such objects do not usually spread the disease.)
A patient with chickenpox can transmit the disease from about 2 days before the appearance of the spots until the end of the blister stage. This period lasts about 5 - 7 days. Once dry scabs form, the disease is unlikely to spread.
Most schools allow children with chickenpox back 10 days after onset. Some require children to stay home until the skin has completely cleared, although this is not necessary to prevent transmission.
Risk Factors for Shingles (Herpes Zoster)
About 500,000 cases of shingles occur each year in the U.S. Anyone who has had chickenpox has risk for shingles later in life, which means that 90% of adults in the U.S. are at risk for shingles. Shingles occurs, however, in 10 - 20% of these adults over the course of their lives, so certain factors must exist to increase the risk for such outbreaks.
The Aging Process. The risk for herpes zoster increases as people age, and the overall number of cases will undoubtedly increase as the baby boomer generation gets older. One study estimated that a person who reaches age 85 has a 50% chance of having herpes zoster. The risk for postherpetic neuralgia (PHN) is also highest in older people with the infection and increases dramatically after age 50. PHN is persistent pain and is the most feared complication of shingles.
Immunosuppression. People whose immune systems are impaired from diseases such as AIDS or childhood cancer have a risk for herpes zoster that is much higher than those with healthy immune systems. Herpes zoster in people who are HIV-positive may be a sign of full-blown AIDS. Certain drugs used for HIV, called protease inhibitors, may also increase the risk for herpes zoster.
Cancer. Cancer places people at risk for herpes zoster. At highest risk are those with Hodgkin's disease (13 - 15% of these patients develop shingles). About 7 - 9% of patients with lymphomas, and 1 - 3% of patients with other cancers, have herpes zoster. Chemotherapy itself increases the risk for herpes zoster.
Immunosuppressant Drugs. Patients who take certain drugs that suppress the immune system are at risk for shingles (as well as other infections). They include:
- Azathioprine (Imuran)
- Chlorambucil (Leukeran)
- Cyclophosphamide (Cytoxan)
- Cyclosporine (Sandimmune, Neoral)
- Cladribine (Leustatin)
- Infliximab (Remicade)
- Adalimumab (Humira)
These drugs are used for patients who have undergone organ transplantation and are also used for severe autoimmune diseases caused by the inflammatory process. Such disorders include rheumatoid arthritis, systemic lupus erythematosus, diabetes, multiple sclerosis, Crohn's disease, and ulcerative colitis.
Risk Factors for Shingles in Children. Although most common in adults, shingles occasionally develops in children. Children with immune deficiencies are at highest risk. Children with no immune problems but who had chickenpox before they were 1 year old also have a higher risk for shingles.
Risk for Recurrence of Shingles. Shingles can recur, but the risk is low (1 - 5%). Evidence suggests that a first zoster episode boosts the immune system to ward off another attack.
Chickenpox (varicella) rarely causes complications, but it is not always harmless. It can cause hospitalization and, in rare cases, death. Fortunately, since the introduction of the vaccine in 1995, hospitalizations have declined by nearly 90%, and there have been few fatal cases of chickenpox.
Adults have the greatest risk for dying from chickenpox, with infants having the next highest risk. Males (both boys and men) have a higher risk for a severe case of chickenpox than females. Children who catch chickenpox from family members are likely to have a more severe case than if they caught it outside the home. The older the child, the higher the risk for a more severe case. But even in such circumstances, chickenpox is rarely serious in children. Other factors put individuals at specifically higher risk for complications of chickenpox.
Recurrence of Chickenpox and Reactivation as Shingles
Recurrence of Chickenpox. Recurrence of chickenpox is possible, but uncommon. One episode of chickenpox usually means lifelong immunity against a second attack. However, people who have had mild infections may be at greater risk for a breakthrough infection later on.
Reactivation of the Virus as Shingles (Herpes Zoster). The major long-term complication of varicella is the later reactivation of the herpes zoster virus and the development of shingles. Shingles occurs in about 20% of people who have had chickenpox.
Specific Complications of Chickenpox (Varicella)
Aside from itching, the complications described below are very rare.
Itching. Itching, the most common complication of the varicella infection, can be very distressing, particularly for small children. Certain home remedies are available that can alleviate the discomfort. [See: "Treatment for Chickenpox" section below.]
Secondary Infection and Scarring. Small scars may remain after the scabs have fallen off, but they usually clear up within a few months. In some cases, a secondary infection may develop at sites which the patient has scratched. The infection is usually caused by the bacteria Staphylococcus aureus or Streptococcus pyogenes. Permanent scarring may occur as a result. Children with chickenpox are at much higher risk for this complication than adults are, possibly because they are more likely to scratch.
Ear Infections. Some children are at higher risk for ear infections from chickenpox. Hearing loss is a very rare result of this complication.
Bacterial Superinfection. Bacterial superinfection of the skin caused by group A streptococcus is the most common serious complication of chickenpox (but it is still rare). The infection is usually mild, but if it spreads in deep muscle, fat, or in the blood, it can be life threatening. Infection can cause serious conditions, such as necrotizing fasciitis (the so-called flesh-eating bacteria) and toxic shock syndrome (TSS).
- A persistent or recurrent high fever
- Redness, pain, and swelling in the skin and the tissue beneath
Pneumonia. Pneumonia is suspected if coughing and abnormally rapid breathing develop in patients who have chickenpox. Adults and adolescents with chickenpox are at some risk for serious pneumonia. Pregnant women, smokers, and those with serious medical conditions are at higher risk for pneumonia if they have chickenpox. Oxygen and intravenous acyclovir are key treatments for this condition. Pneumonia that is caused by varicella can result in lung scarring, which may impair oxygen exchange over the following weeks, or even months.
Effects on the Brain and Central Nervous System.
- Inflammation in the Brain. Encephalitis and meningitis, infections or inflammation in the central nervous systems, have occurred in a few varicella patients, both children and adults. This condition can be very dangerous, causing coma and even death. Fortunately, it is extremely rare. Symptoms vary. The patient may become over-agitated or may exhibit loss of coordination and poor balance.
- Stroke. Although stroke in children is extremely rare, a condition called cerebral vasculitis, in which blood vessels in the brain become inflamed, has been associated with varicella-zoster. Varicella may be a factor in some cases of stroke in young adults.
Effects During Pregnancy. The risk for chickenpox in a pregnant woman is very low (1 - 7 cases in 10,000). However, chickenpox places the woman at risk for life-threatening pneumonia. Infection in the pregnant woman in the first trimester also poses a 1 - 2% chance for infecting the developing fetus, which is an extremely serious condition. (Herpes zoster is even rarer in pregnant women, and there is almost no risk for the unborn child in such cases.)
Disseminated Varicella. Disseminated varicella, which develops when the virus spreads to organs in the body, is extremely serious and is a major problem for patients with compromised immune systems. An immune system may become compromised as a result of diseases such as AIDS, inherited conditions, or certain drugs. For example, disseminated varicella occurs in up to 35% of children with chickenpox who are undergoing cancer chemotherapy. In such cases, mortality rates are between 7 - 30%.
Reye Syndrome. Reye syndrome, a disorder that causes sudden and dangerous liver and brain damage, is a side effect of aspirin therapy in children who have chickenpox or influenza. The disease can lead to coma and is life threatening. Symptoms include rash, vomiting, and confusion beginning about a week after the onset of the disease. Because of the strong warnings against children taking aspirin, this condition is, fortunately, very rare. Children should never be given aspirin when they have a viral infection or fever. Acetaminophen (Tylenol) is the preferred drug for fever or pain in patients younger than age 18 years.
Other Rare Complications of Chickenpox. Other extremely rare complications of varicella include problems in blood clotting and inflammation of the nerves in the hands and feet. Inflammation can also occur in other areas of the body, such as the heart, testicles, liver, joints, or kidney.
Complications of Shingles (Herpes Zoster)
Pain. The pain and discomfort of the active herpes zoster infection is the primary symptom and complication of herpes zoster. The pain usually takes one of these forms:
- Continuous burning or aching pain
- Periodic piercing pain
- Spasm similar to electric shock
Such experiences may also be more intense than even normal responses, defined in the following ways:
- Allodynia is pain caused by factors, such as a light touch of clothing or a cold wind, which occurs from very little stimulation.
- Hyperalgesia is a more intense painful response to a normally painful experience.
The pain tends to be more severe at night. Temperature changes can also affect pain. The pain may extend beyond the areas of the initial zoster attack. In most cases, it does not affect daily life. Rarely, however, the pain of herpes zoster affects sleep, mood, work, and overall quality of life. This can lead to fatigue, loss of appetite, depression, social withdrawal, and impaired daily functioning.
Itching. Many patients report itching (postherpetic itch) as the primary symptom, rather than pain. In rare cases, it can be disabling.
Postherpetic Neuralgia (PHN). Postherpetic neuralgia (PHN) is pain that persists for longer than a month after the onset of herpes. It is the most common severe complication of shingles. It is not clear why PHN occurs. Some theories for its development are:
- The herpes zoster virus appears to produce persistent inflammation in the spinal cord that causes long-term damage, including nerve scarring.
- Nerves that are injured in the initial attack may heal abnormally and provoke an exaggerated response in the brain that produces intense sensitivity or pain.
In people with herpes zoster, the risk of developing PHN ranges from 10 - 70%. In general, however, the risk is likely to be in the lower range. People with impaired immune systems do not seem to be at any higher risk for persistent PHN than those with normal immune systems.
The following are risk factors for PHN:
- Age. PHN affects about 25% of herpes zoster patients over 60 years old. The older a person is, the longer PHN is likely to last. It rarely occurs in people under age 50.
- Gender. Some studies suggest that women may be at slightly higher risk for PHN than men.
- Severe or Complicated Shingles. People who had prodromal symptoms or a severe attack (numerous blisters and severe pain) during the initial shingles episode are also at high risk for PHN. The rate is also higher in people whose eyes have been affected by zoster.
In most cases, PHN resolves within 3 months. Some doctors define persistent pain after a herpes zoster attack as subacute herpetic neuralgia if it lasts between 1 - 3 months and as PHN only if it lasts beyond 3 months. Studies report that only about 10% of patients experience pain after a year. Unfortunately, when PHN is severe and treatments have not been very effective, the persistent pain and abnormal sensations can be profoundly frustrating and depressing for patients.
Secondary Infection in the Blisters. If the blistered area is not kept clean and free from irritation, it may become infected with group A Streptococcus or Staphylococcus bacteria. If the infection is severe, scarring can occur.
Guillain-Barre Syndrome. Guillain-Barre syndrome is caused by inflammation of the nerves and has been associated with a number of viruses, including herpes zoster. The arms and legs become weak, painful, and, sometimes, even paralyzed. The trunk and face may be affected. Symptoms vary from mild to severe enough to require hospitalization. The disorder resolves in a few weeks to months. Other herpes viruses (cytomegalovirus and Epstein-Barr), or bacteria (Campylobacter) may have a stronger association with this syndrome than herpes zoster.
Effects on Face and Ears.
- Ramsay Hunt Syndrome. Ramsay Hunt syndrome occurs when herpes zoster causes facial paralysis and rash on the ear (herpes zoster oticus) or in the mouth. Symptoms include severe ear pain and hearing loss, ringing in the ear, loss of taste, nausea, vomiting, and dizziness. Ramsay Hunt syndrome may also cause a mild inflammation in the brain. The dizziness may last for a few days, or even weeks, but usually resolves. Severity of hearing loss varies from partial to total; however, this too usually always goes away. Facial paralysis, on the other hand, may be permanent.
- Bell's Palsy. Bell's palsy is partial paralysis of the face. There is some indication that this syndrome may suggest a reactivation of herpes zoster, even if no rash appears.
Sometimes, it is difficult to distinguish between Bell's palsy and Ramsay Hunt syndrome, particularly in the early stages. In general, Ramsay Hunt syndrome tends to be more severe than Bell's palsy.
Effects on the Brain. Inflammation of the membrane around the brain (meningitis) or in the brain itself (encephalitis) is a rare complication in people with herpes zoster. The encephalitis is generally mild and resolves in a short period. In rare cases, particularly in patients with impaired immune systems, it can be severe and even life threatening.
Effects in the Urinary Tract. In rare situations, herpes zoster can infect the urinary tract and cause difficulty in urination. The condition is temporary but may require a catheter for patients who have trouble urinating.
Infections in the Eye. If shingles occurs in the face, the eyes are at risk, particularly if the path of the infection follows the side of the nose. If the eyes become involved ( herpes zoster ophthalmicus), a severe infection can occur that is difficult to treat and can threaten vision. AIDS patients may be at particular risk for a chronic infection in the cornea of the eye.
Herpes zoster can also cause a devastating infection in the retina called imminent acute retinal necrosis syndrome. In such cases, visual changes develop within weeks or months after the herpes zoster outbreak has resolved. Although this complication usually follows a herpes outbreak in the face, it can occur after an outbreak in any part of the body. Prompt treatment with acyclovir can often halt its progress, at least in people with healthy immune systems. Either acyclovir or valacyclovir, a similar drug, may prevent other eye complications, such as conjunctivitis (pink eye), inflammation of the cornea, and pain.
Disseminated Herpes Zoster. As with disseminated chickenpox, disseminated herpes zoster, which spreads to other organs, can be serious to life-threatening, particularly if it affects the lungs. People with compromised immune systems are at greatest danger, with risk of 5 - 25%. It is very rare in people with healthy immune systems.
In very rare cases, herpes zoster has been associated with Stevens-Johnson syndrome, an extensive and serious condition in which widespread blisters cover mucous membranes and large areas of the body.
High-Risk Candidates for Complications of Chickenpox, Shingles, or Both
Elderly people. The older the patient, the higher the risk for complications from either chickenpox or shingles. Adults who smoke are at particularly higher risk for pneumonia from chickenpox.
Patients with Serious Illnesses. People with serious illnesses may be at risk for complications of the varicella-zoster virus. Patients with diseases, such as Hodgkin's disease, who receive bone marrow or stem cell transplants are at higher risk for herpes zoster and its complications.
Pregnant Women. Pregnant women who become infected with the varicella-zoster virus, whether in the form of chickenpox or shingles, are at increased risk for serious pneumonia.
- The risk for the infant is lower or higher depending on when the mother became infected.
- Chickenpox in the mother during early pregnancy poses a slightly increased risk for birth defects in the infant.
- The highest risk for birth defects is about 2%, which usually occurs if the mother has chickenpox between the 13th and 20th week. Even in such cases, birth defects may only result in minor skin abnormalities. More serious defects include a smaller than normal head, eye problems, low birth weight, and mental retardation.
- If women develop chickenpox (not shingles) within 5 days before and 2 days after delivery, their newborns are at risk for life-threatening varicella.
Newborns and Infants. Chickenpox in newborns is a life-threatening condition. Although chickenpox can still be very dangerous in older infants, most are protected by antibodies in breast milk from mothers who have had chickenpox. Children under age 1 who develop chickenpox are at higher risk for childhood shingles. All infants should have as little exposure as possible to people with chickenpox.
Symptoms of Chickenpox
The time between exposure to the virus and eruption of symptoms is called the incubation period. For chickenpox, this period is 10 - 20 days. The patient often develops fever, headache, swollen glands, and other flu-like symptoms before the typical rash appears. While fevers are low grade in most children, some can reach 105 F.
These symptoms subside once the rash breaks out. One or more tiny raised red bumps appear first, most often on the face, chest, or abdomen. They become larger within a few hours and spread quickly (sprout), eventually forming small blisters on a red base. The numbers of blisters vary widely. Some patients have only a few spots, others can develop hundreds. Each blister is filled with clear fluid that becomes cloudy in several days. It takes about 4 days for each blister to dry out and form a scab. During its course, the rash itches, sometimes severely. Usually separate crops of blisters occur over 4 - 7 days, the entire disease process lasting 7 - 10 days.
Chickenpox itself usually occurs only once, although mild second infections, marked by the telltale rash, have been reported in older children years after their first infection.
Symptoms of a Typical Shingles (Herpes Zoster) Attack
Shingles nearly always occurs in adults. It develops on one side of the body. Usually two, and sometimes three, identifiable symptom stages occur:
- The first is known as the prodrome, a cluster of warning symptoms that appear before the outbreak of the infection.
- The second stage comprises the symptoms of the active infection itself.
- In many patients, a third syndrome known as postherpetic neuralgia later develops.
Pain is so common to all stages of herpes zoster that doctors often refer to all syndromes with a single term: Zoster-Associated Pain (ZAP).
- Pain is the primary early symptom for shingles, and it occurs in all patients. The pain most often occurs in the skin at the site of the re-activated virus. The pain may be experienced as sharp, aching, piercing, tearing, or similar to an electric shock.
- The affected skin may itch, feel numb, and be unbearably sensitive to touch. Often the patient experiences a combination of these sensations along with pain.
- In addition, some patients may have flu-like symptoms such as muscle aches. (Some people have fever, but it is uncommon.)
The prodrome stage lasts 1 - 5 days before the infection becomes active and the skin rash erupts. Occasionally, the pain can last weeks or even months before the rash erupts.
Active Shingles. The rash that marks the active infection follows the same track of inflamed nerves as the prodrome pain. Between 50 - 60% of cases occur on the trunk. The second most common site is the head, particularly on one side of the face. It may also erupt on the neck or lower back. If the face is affected, there is a danger that the infection can spread to the eye or mouth. A rash that follows the side of the nose is a warning that the cornea of the eye is in danger.
The active infection is typically marked by the following sequence:
- A rash appears, starting as well-defined, small, red, clear spots.
- Within 12 - 24 hours, these pimples develop into small fluid-filled blisters.
- The blisters grow, merge, and become pus-filled.
- Pain is common during the active infection.
- Within about 7 - 10 days (as with chickenpox), the blisters form crusts and heal. In some cases it may take as long as a month before the skin clears completely. Healing takes even longer in patients who have impaired immune systems, and, in such cases, the blisters may last for months.
Zoster Sine Herpete. Sometimes pain develops without a rash, a condition known as zoster sine herpete. This usually occurs in elderly patients. Symptoms include burning or shooting pain, numbness, tingling, itching, headache, fever, chills, and nausea. An accurate early diagnosis of shingles in such cases is often difficult. Some evidence suggests that some cases of Bell's palsy (in which part of the face becomes paralyzed) might actually be an indication of zoster sine herpete.
Postherpetic Neuralgia. Postherpetic neuralgia (PHN) is pain that persists for longer than a month after the onset of herpes zoster. PHN occurs in about 10 - 20% of patients who have shingles.
Both chickenpox (varicella) and shingles (zoster) can usually be diagnosed by symptoms alone. If a diagnosis is still unclear after a physical examination, diagnostic tests may be required.
Ruling out Other Disorders
Either variation of the virus may be confused with other disorders.
Ruling out Disorders that Resemble Chickenpox. Chickenpox, particularly in early stages, may be confused with herpes simplex (the disorder more commonly referred to as "herpes"), or impetigo, insect bites, and scabies.
Ruling out Disorders that Resemble Shingles. The early prodrome stage of shingles can cause severe pain on one side of the lower back, chest, or abdomen before the rash appears. It therefore may be mistaken for disorders, such as gallstones, that cause acute pain in internal organs.
In the active rash stage, shingles may be confused with herpes simplex, particularly in young adults, if the blisters occur on the buttocks or around the mouth. Herpes simplex, however, does not usually generate chronic pain.
A diagnosis may be difficult if herpes zoster takes a non-typical course in the face, such as with Bell's palsy or Ramsay Hunt syndrome, or if it affects the eye or causes fever and delirium.
Test to Identify the Virus
In most cases of chickenpox and shingles, the symptoms alone are enough for a health care provider to make a diagnosis. If the symptoms are not straightforward in some patients, such as those who are immunosuppressed, the doctor performs one or more additional tests to detect the virus itself. The tests usually aim to distinguish between varicella-zoster and herpes simplex viruses.
Virus Culture. A viral culture uses specimens taken from the blister, fluid in the blister, or sometimes spinal fluid. They are sent to a laboratory, where it takes 1 - 14 days to detect the virus in the preparation made from the specimen. It is also sometimes used in vaccinated patients to determine if a varicella-like infection is caused by a natural virus or by the vaccine. This test is useful, but it is sometimes difficult to recover the virus from the samples.
Immunofluorescence Assay. Immunofluorescence is a diagnostic technique used to identify antibodies to a specific virus. In the case of herpes zoster, the technique uses ultraviolet rays applied to a preparation composed of cells taken from the zoster blisters. The specific characteristics of the light as seen through a microscope will identify the presence of the antibodies. This test is less expensive than a culture, more accurate, and results are faster.
Polymerase Chain Reaction (PCR). Polymerase chain reaction (PCR) techniques use a piece of the DNA of the virus, which is then replicated millions of times until the virus is detectable. This technique is expensive but is useful for unusual cases, such as identifying infection in the central nervous system.
There are two types of varicella vaccines:
- A chickenpox vaccine for vaccinating children, adolescents, and adults
- A shingles vaccine for vaccinating adults age 60 years and older
The live-virus varicella vaccine (Varivax) produces persistent immunity against chickenpox. The vaccine can prevent chickenpox or reduce the severity of the illness if it is used within 3 days, and possibly up to 5 days, after exposure to the infection.
The childhood chickenpox vaccine can also be given as part of a combination vaccine (Proquad) that combines measles, mumps, rubella (together called MMR), and varicella in one product. However, recent data indicate that combining varicella and MMR vaccinations into one shot doubles the risk for febrile (fever-related) seizures in children ages 12 - 24 months compared to giving separate MMR and varicella injections. Parents should consider the lower risk associated with separate injections.
Recommendations for the Chickenpox Vaccine in Children
The U.S. Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices (ACIP) recommends that children receive TWO doses of the chickenpox vaccine with:
- The first dose administered when the child is 12 - 15 months years of age, and
- The second dose administered when the child is 4 - 6 years of age
For children who have previously received one dose of the chickenpox vaccine, the ACIP recommends that they receive a catch-up second dose during their regular doctors visit. This second dose can be given at any time as long as it is at least 3 months after the first dose. Doctors pushed for the new second-dose policy due to a number of recent chickenpox outbreaks among previously vaccinated schoolchildren.
Children most at risk for having chickenpox after having been vaccinated only one time are ages 8 - 12 years and have generally been vaccinated at least 5 years before their current chickenpox infection.
Recommendations for the Chickenpox Vaccine in Adults
The U.S. Centers for Disease Control and Prevention (CDC) recommends that every healthy adult without a known history of chickenpox be vaccinated. Adults should receive 2 doses of the vaccine, 4 - 8 weeks apart. Adults in the following groups should especially consider vaccination:
- Those with high risk of exposure or transmission (hospital or day care workers, parents of young children)
- People who may come in contact with those who have compromised immune systems
- Nonpregnant women of childbearing age
- International travelers
As with other live-virus vaccines, the chickenpox vaccine is not recommended for:
- Women who are pregnant or who may become pregnant within 30 days of vaccination. . (Women who are pregnant and not immunized should receive the first dose of the vaccine upon completion of their pregnancy.)
- People whose immune systems are compromised by disease or drugs (such as after organ transplantation).
Patients who cannot be vaccinated but who are exposed to chickenpox receive immune globulin antibodies against varicella virus. This helps prevent complications of the disease if they become infected.
Side Effects of the Varicella (Chickenpox) Vaccine
- Discomfort at the Injection Site. Fewer than 80% of vaccine recipients have pain, swelling, or redness at the injection site.
- Severe Side Effects. Only about 5% of adverse reactions are serious. These reactions include seizures, pneumonia, anaphylactic reaction, encephalitis, Stevens-Johnsons syndrome, neuropathy, herpes zoster, and blood abnormalities.
- Risk of Transmission. The vaccine may produce a mild rash within about a month of the vaccination, which can transmit chickenpox to others. Individuals who have recently been vaccinated should avoid close contact with anyone who might be susceptible to severe complications from chickenpox until the risk for a rash passes.
- Later Infection. Months or even years after the vaccination, some people develop a mild infection called modified varicella-like syndrome (MVLS). The condition appears to be less contagious and has fewer complications than naturally acquired chickenpox.
In 2006, a shingles vaccine was approved for use in the United States. The zoster vaccine (Zostavax) is a stronger version of the chickenpox vaccine. Study results suggest that the zoster vaccine can prevent about half of all shingles cases and two-thirds of postherpetic neuralgia cases. The CDC recommends that all adults age 60 years and older who have intact immune systems should receive this vaccine. . The vaccine does not appear to not work well in patients age 80 years and older and is generally not recommended for this age group.
Varicella-Zoster Immune Globulin
Varicella-zoster immune globulin (VariZIG) is a substance that mimics the normal immune response against the varicella-zoster virus. It is used to protect high-risk patients who are exposed to chickenpox. Such groups include:
- Pregnant women with no history of chickenpox who have not been previously immunized
- Newborn infants whose mothers had signs or symptoms of chickenpox around the time of delivery (5 days before to 2 days after)
- Premature infants
- Immunocompromised children and adults with no antibodies to VZV
- Recipients of bone-marrow transplants (even if they have had chickenpox)
- Patients with a debilitating disease (even if they have had chickenpox)
For these patients, VariZIG should be given within 96 hours of exposure to someone with chickenpox. (Note: VariZIG is a new formulation of an older drug called VZIG, which is no longer being produced.)
Treatment for Chickenpox
Acetaminophen. Patients with chickenpox do not have to stay in bed unless fever and flu symptoms are severe. To relieve discomfort, a child can take acetaminophen (Tylenol), with doses determined by the doctor. A child should never be given aspirin, or medications containing aspirin, as aspirin increases the risk for a dangerous condition called Reye syndrome.
Soothing Baths. Frequent baths are particularly helpful in relieving itching, when used with preparations of finely ground (colloidal) oatmeal. Commercial preparations (Aveeno) are available in drugstores, or one can be made at home by grinding or blending dry oatmeal into a fine powder. Use about 2 cups per bath. The oatmeal will not dissolve, and the water will have a scum. Adding baking soda (1/2 - 1 cup) to a bath may also help.
Lotions. Patients can apply calamine lotion and similar over-the-counter preparations to the blisters to help dry them out and soothe the skin.
Antihistamines. For severe itching, diphenhydramine (Benadryl) is useful and may help children sleep.
Preventing Scratching. Small children may have to wear mittens so that they don't scratch the blisters and cause a secondary infection. All patients with varicella, including adults, should have their nails trimmed short.
Acyclovir for Chickenpox
Acyclovir is an antiviral drug that may be used in adult varicella patients or those of any age with a high risk for complications and severe forms of chickenpox. The drug may also benefit smokers with chickenpox, who are at higher than normal risk for pneumonia. Some doctors recommend its use for children who catch chickenpox from other family members because such patients are at risk for more serious cases. To be effective, oral acyclovir must be taken within 24 hours of the onset of the rash. Early intravenous administration of acyclovir is an essential treatment for chickenpox pneumonia.
Treatment for an Acute Shingles Attack
The treatment goals for an acute attack of herpes zoster include:
- Reduce pain
- Reduce discomfort
- Hasten healing of blisters
- Prevent the disease from spreading
Over-the-counter (OTC) remedies are often effective in reducing the pain of an attack. Antiviral drugs (acyclovir and others), oral corticosteroids, or both are sometimes given to patients with severe symptoms, particularly if they are older and at risk for postherpetic neuralgia (PHN). In addition, psychological therapies aimed at coping and reducing the effects of pain may be useful.
Home Remedies for Shingles
Applied Cold. Cold compresses soaked in Burrow's solution (an OTC remedy) and cool baths may help relieve the blisters. It is important not to break blisters as this can cause infection. Doctors advise against warm treatments, which can intensify itching. Patients should wear loose clothing and use clean loose gauze coverings over the affected areas.
Itch Relief. In general, to prevent or reduce itching, home treatments are similar to those used for chickenpox. Patients can try antihistamines (particularly Benadryl), oatmeal baths, and calamine lotion.
Over-the-Counter Pain Relievers. For an acute shingles attack, patients may take over-the-counter pain relievers:
- Children should take acetaminophen. (Shingles is very rare in children.)
- Adults may take aspirin or other nonsteroidal anti-inflammatory drugs, such as ibuprofen (Advil or other brands). These remedies, however, are not very effective for postherpetic neuralgia.
Nucleoside Analogues and Other Antiviral Drugs
Nucleoside Analogues. The best class of drugs developed against varicella-zoster are those known as nucleoside, or guanosine, analogues. These medicines block viral reproduction. None of these drugs can actually destroy the virus and cure the disease, but they can significantly reduce the severity of the attack, hasten healing, and reduce the duration. They may also reduce the risk of postherpetic neuralgia.
These anti-viral drugs are usually taken for 7 days. Ideally they should be started within 72 hours of the onset of infection. The earlier they are given the more effective these drugs are, but they can be helpful even if treatment is started after 3 days. Combinations of antiviral therapy with other drugs, such as tricyclic antidepressants or anticonvulsant drugs, are under investigation
Acyclovir (Zovirax), famciclovir (Famvir), and valacyclovir (Valtrex) are approved for shingles. Acyclovir is the oldest, most studied of these drugs, but either famciclovir (Famvir) or valacyclovir (Valtrex), which are both metabolized into acyclovir, are now preferred to treat herpes zoster in most patients because they require fewer daily doses than the five doses needed with acyclovir.
Because herpes zoster tends to resolve fairly quickly in young adults, these drugs are more important for patients at greatest risk for complications or persistent pain. They include:
- Elderly people
- Those with infections that threaten the eye
- Patients who are HIV positive or immunocompromised in other ways
- Patients whose infection covers a larger-than-average surface area of the skin
- Those with very severe pain
These drugs appear to have little or no harmful effect on healthy cells and can penetrate most body tissues, including cerebrospinal fluid. Evidence to date suggests that they are safe during pregnancy.
Possible side effects of nucleoside analogues include rash, headache, fatigue, tremor, nausea and vomiting. Seizures are a very rare side effect. Patients with AIDS or other diseases that compromise the immune system are at increased risk for kidney damage and blood clots. Patients with suppressed immune systems are also more likely to have viral resistance to these drugs. These drugs are safe to take during pregnancy.
Foscarnet. Foscarnet (Foscavir) is a powerful antiviral drug known as a pyrophosphate analogue. It is used in cases of VZV strains that have become resistant to acyclovir and similar drugs. Administered intravenously, the drug can have toxic effects. It can impair kidney function (which is reversible) and cause seizures. Fever, nausea, and vomiting are common side effects. It can also cause ulcers on genital organs. As with other drugs, it does not cure shingles.
Brivudin. Brivudin (Helpin, Zostex), another antiviral drug, is not available in the U.S. It needs to be taken only once a day.
Oral corticosteroids, including prednisolone or prednisone, are powerful anti-inflammatory medications. They have some benefit for reducing pain in the first 2 weeks or so of an attack, when used with acyclovir or another nucleoside analogue. (They are not recommended without a nucleoside analogue.) They also may be helpful for improving symptoms of Bell's palsy and Ramsay Hunt syndrome. Corticosteroids do not appear to prevent a further shingles attack or reduce the risk for PHN. Side effects of corticosteroids can be severe, and patients should take oral steroids at as low a dose, and for as short a time, as possible. (Injected or intravenous steroids, however, may offer specific relief for PHN without significant side effects.)
Treatment for Postherpetic Neuralgia
Postherpetic neuralgia (PHN) is difficult to treat. Once PHN develops, a patient may need a multidisciplinary approach that involves a pain specialist, psychiatrist, primary care physician, and other health care providers.
The American Academy of Neurology (AAN) treatment guidelines for postherpetic neuralgia recommend:
- Tricyclic antidepressants (amitriptyline, nortriptyline, desipramine, maprotiline)
- Anticonvulsants (gabapentin and pregabalin)
- Lidocaine skin patches
- Opioids (oxycodone, methadone, morphine)
Topical Substances for Postherpetic Neuralgia
Topical Pain Relievers. Creams, patches, or gels containing various substances can provide some pain relief.
- Lidocaine and Other Anesthetic Patches. A patch that contains the anesthetic lidocaine (Lidoderm) is approved specifically for postherpetic neuralgia (PHN). One to four patches can be applied over the course of 24 hours. Another patch (EMLA) contains both lidocaine and prilocaine, a second anesthetic. The most common side effects are skin redness or rash.
- Capsaicin (Zostrix) is prepared from the active ingredient in hot chili peppers. An ointment form has been approved for postherpetic neuralgia. Its benefits are limited, however. A patch form that uses a higher than standard dose may work better. Patients should not use capsaicin until the blisters have completely dried out and are falling off the skin. They should handle capsaicin ointment using a glove, and apply it to affected areas three or four times daily. The patient will usually feel a burning sensation when the drug is first applied, but this sensation diminishes with use. It may take up to 6 weeks for the patient to feel the ointment's full effect, and about a third of patients cannot tolerate the burning sensation.
- Topical Aspirin. Topical aspirin, known chemically as triethanolamine salicylate (Aspercreme), may bring relief.
- Menthol-Containing Preparations. Topical drugs containing menthol, such as high-strength Flexall 454, may be helpful.
Skin Coolants. Ethyl chloride (Chloroethane) and fluori-methane are chemicals that cool the blood vessels in the skin. Sprays that contain these chemicals are not anesthetics, but they are used to inactivate the sensitive areas. To use the spray, the patient must be in a comfortable position. The spray bottle is held upside-down, about 12 - 18 inches from the targeted area. The face must be covered if the spray is being used near the head.
Tricyclic antidepressants relieve pain in up to two-thirds of patients. These drugs not only relieve depression, which can be common in PHN sufferers, but certain tricyclics specifically block sodium channels, which play a role in causing pain in PHN. Nortriptyline (Pamelor, Aventyl), amitriptyline (Elavil, Endep), and desipramine (Norpramin) are standard drugs.
They may be more effective when started during the first year after symptoms begin. It may take several weeks for the drugs to become fully effective. They do not work as well in patients who have burning pain or allodynia (pain that occurs with normally non-painful stimulus, such as a light touch or wind).
Unfortunately, tricyclics have side effects that are particularly severe in the elderly, who are also more likely to have PHN. Desipramine and nortriptyline have fewer side effects than amitriptyline and are preferred for older patients. Side effects include dry mouth, blurred vision, constipation, dizziness, difficulty urinating, disturbances in heart rhythms, and an abrupt drop in blood pressure when standing up.
Anticonvulsant (Anti-Seizure) Drugs
Certain anticonvulsant drugs have effects that block over-excitation of nerve cells and may be helpful for PHN patient. (Anticonvulsant drugs are also known as anti-seizure drugs.)
Gabapentin. Gabapentin (Neurontin) was the first anticonvulsant drug approved for PHN. Studies suggest significant pain relief in patients with PHN and reduction in the use of opioids. Many patients also report improved quality of life, including better sleep. Gabapentin is also showing promise in combination with valacyclovir for reducing pain from an acute herpes zoster attack.
Side effects include skin rashes, mood swings or thoughts of suicide, headache, dizziness, sleepiness, swelling, and upset stomach. Some people have visual disturbances, ringing in the ears, agitation, or odd movements when drug levels are at their peak. These side effects may limit their value in older people who are at risk of falling. In general, however gabapentin is safer than tricyclic antidepressants for elderly patients.
Pregabalin. Pregabalin (Lyrica) is similar to gabapentin. Like gabapentin, side effects can include sleepiness and dizziness
Other Anticonvulsant Drugs. The AAN guidelines found insufficient evidence to recommend carbamazepine (Tegretol).
Opioids and Opioid-like Drugs
Opioids. Patients with severe pain that does not respond to tricyclic antidepressants may need powerful painkilling opioid drugs. They may be taken by mouth or delivered through a skin patch. Oxycodone is the standard opioid for PHN. Morphine is also used. Methadone (Dolophine) may also be helpful. Constipation, drowsiness, and dry mouth are common side effects of opioids.
Tramadol. Tramadol (Ultram) is a pain reliever that has been used as an alternative to opioids. It has opioid-like properties but is not as addictive. (Dependence and abuse have been reported, however.) It can cause nausea but not severe gastrointestinal problems, as NSAIDs can. Studies suggest it might be very helpful for PHN patients, particularly those with heart problems or other conditions that restrict tricyclic antidepressants.
Other Medical Treatments
Antiviral Drugs. Researchers are investigating whether treatment with antiviral drugs may help reduce the pain associated with postherpetic neuralgia.
Surgery. Certain surgical techniques in the brain or spinal cord attempt to block nerve centers associated with postherpetic neuralgia. These methods carry risk for permanent damage, however, and should be used only as a last resort when all other methods have failed and the pain is intolerable. Most studies indicate that surgery does not relieve PHN pain.
Stress Reduction Techniques. A number of relaxation and stress-reduction techniques may be helpful for managing chronic pain. They include meditation, deep breathing exercises, biofeedback, and muscle relaxation. These techniques may apply to patients with severe pain from acute infection or persistent long-term postherpetic neuralgia. [For more information, see In-Depth Report #31: Stress.]
Behavioral Cognitive Therapy. Behavioral cognitive therapy is showing benefit in enhancing patients' beliefs in their own abilities for dealing with pain. Using specific tasks and self-observation, patients gradually shift their fixed ideas that they are helpless against the pain that dominates their lives to the perception that it is a manageable experience. The skill of the therapist is very important to its success.
Many people with chronic pain such as PHN turn to alternative treatments for relief. Aside from hypnosis, little evidence indicates that these treatments work for PHN. Acupuncture is one such unproven remedy.
- www.cdc.gov -- Centers for Disease Control and Prevention
- www.niaid.nih.gov -- National Institute of Allergy and Infectious Diseases
- www.ninds.nih.gov -- National Institute of Neurological Disorders and Stroke
- www.aan.com -- American Academy of Neurology
- www.neuropathy.org -- Neuropathy Association
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Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.