WebMD - Shingles and Chicken Pox (Varicella-Zoster Virus)

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http://my.webmd.com/content/article/1680.50895 Shingles and Chicken Pox (Varicella-Zoster Virus)Although they are caused by the same organism - Varicella-Zoster Virus - chicken pox and shingles have different presentations and outcomes; shingles being a years-later reactivation of chicken pox. Read this article to clear up the confusion, and...

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What Are Shingles and Chickenpox (Varicella-Zoster Virus)?

Shingles and chickenpox were once considered separate disorders. It is now known that they are both caused by a single virus of the herpes family known as varicella-zoster virus (VZV). The virus is still referred to by separate terms, depending on whether it is the primary infection (varicella) that causes chicken pox or if it is the reactivation of the virus (herpes zoster) that causes shingles. The word herpes is derived from the Greek word "herpein", which means "to creep", a reference to a characteristic pattern of skin eruptions. VZV belongs to a group of herpes viruses that includes seven human viruses, as well as many animal viruses. In addition to varicella-zoster virus, the other human herpes viruses are herpes simplex virus (the most common), cytomegalovirus, Epstein-Barr virus (the cause of mononucleosis), human herpesvirus type 6 (the cause of roseola), and herpesvirus type 7 (HHV-7). All share some common properties, including a pattern of active symptoms followed by latent inactive periods that can last for months, years, or even for a lifetime. These herpes viruses are similar in shape and size and reproduce within the structure of a cell. The particular cell depends upon the specific herpes virus.

In the case of VZV, during a bout of chickenpox, the virus (referred to as varicella at this stage) spreads through the blood to the skin. The virus also travels to nerve cells called dorsal root ganglia, which are bundles of nerves that transmit sensory information from the skin to the brain. The sensory nerves most often affected are those in the face or the trunk. The virus remains inactive (latent) in these nerves for years, often for a lifetime. If the virus becomes active, however, it causes the disorder known as shingles, and the virus is then referred to as herpes zoster. It is not clear why the virus reactivates in some people and not in others. In many cases, the immune system has become impaired or suppressed from certain conditions, such as AIDS or other immunodeficient diseases, certain cancers, or certain drugs that suppress the immune system.

What Are the Symptoms of Chickenpox and Shingles?

Symptoms of Chickenpox (Varicella)

When patients with chicken pox cough or sneeze, they expel tiny droplets that carry the varicella-zoster virus (VZV). If a person who has never had chicken pox inhales these particles, the virus enters the lungs and is carried through the blood to the skin where it causes the typical rash of chicken pox. This incubation period (the time between exposure to the virus and eruption of symptoms) is between 10 and 20 days. Even before the typical rash appears, the patient often develops fever, headache, swollen glands, and other flu-like symptoms. (Although fevers are low grade in most children, some can reach up to 105 degrees Fahrenheit.) The patient usually begins to feel better 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, eventually forming small blisters on a red base that have been described as dewdrops on rose petals. Their number varies 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 four 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 four to seven days, and the entire disease process lasts between seven and 10 days.

Symptoms of Shingles (Herpes Zoster)

Shingles nearly always occurs in adults and develops on one side of the body. Usually two identifiable symptom stages occur. The first is known as the prodrome, which are 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 develops. In fact, physicians often refer to all three syndromes with a single term -- zoster-associated pain (ZAP).

Prodrome. The primary early symptom for shingles is pain in the area of skin that contains the sensory nerves connecting to an inflamed dorsal root ganglion harboring the reactivated virus. The affected skin may itch, feel numb, be unbearably sensitive to touch, or pain may be experienced as sharp, aching, piercing, tearing, or similar to an electric shock. Often the patient experiences a combination of these sensations. In addition, some patients may have flu-like symptoms, including fever and muscle aches. The prodrome stage usually lasts a few days before the infection becomes active and the skin rash erupts. Occasionally, the pain can last for weeks before the rash erupts.

Active Shingles. The active infection is marked by a rash, which starts as well-defined, small, red, clear spots; they follow the same track of inflamed nerves as the prodrome pain. Within 12 to 24 hours, these pimples develop into small fluid-filled blisters. The blisters grow, merge, and become pus-filled. Within about seven to ten days, as with chicken pox, they form crusts and heal. Between 50% and 60% of cases occur on the trunk, but other common sites include one side of the face, 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 endangered. Pain is common during the active infection.

Although the active phase usually lasts about a week, in some cases it may take as long as a month before the skin clears completely. Healing takes much longer in patients who have impaired immune systems; in such cases, the blisters may persist for up to months.

Zoster Sine Herpete. In a condition known as zoster sine herpete, pain is the only symptom and no rash appears. One study suggested that some cases of Bell's palsy, in which part of the face becomes paralyzed, may actually be due to zoster sine herpete and, therefore, treatable with anti-viral drugs.

Postherpetic Neuralgia. Postherpetic neuralgia (PHN), the most common long-term complication of shingles, is pain that persists for longer than a month after the onset of herpes zoster. The pain usually takes one or more of three forms; it can be a continuous burning or aching pain, a periodic piercing pain, or pain that occurs from very little stimulation, such as a light touch of clothing. It 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, and some areas have no feeling at all.

A number of factors appear to cause the pain and aberrant sensations of PHN. Numbness and odd sensations may be due to skin and nerve scarring that result from persistent inflammation. Injured nerves or nerve fibers that regrow abnormally may send messages back to the central nervous system that provoke an exaggerated response by the brain, signaling intense sensitivity or pain.

Estimates for the risk of PHN range from 10% to 70%, depending on susceptibility. Very few children develop PHN, while, in herpes zoster patients over 55 years old, the risk for postherpetic neuralgia is 27%, and in those over 60, it is almost half. And the older a person is, the longer PHN is likely to last; only 4% of those under 20 have PHN that lasts more than year compared to 48% of those over 70. Women may be at slightly higher risk than men. The rate is also higher in people whose eyes have been affected by zoster. People with impaired immune systems do not seem to be at any higher risk than those with normal immune systems.

To date, treatments have not been very effective, and for these patients, the persistent pain and abnormal sensations can be profoundly frustrating and depressing. Both the short and long-term pain of herpes zoster affects sleep, mood, work, and overall quality of life.

Who Gets Chicken Pox and Shingles?

Risk Factors for Chicken Pox (Varicella)

Chicken pox favors no race or gender and is so contagious that, unless they have been vaccinated, few people escape this common disease; 75% to 90% of cases occur in children under 10 years of age.

Transmission of Chicken Pox. The disease usually occurs in late winter and early spring months and is usually spread through sneezing, coughing, and breathing. It can also be transmitted from direct contact with the open sores. (Clothing, bedding, and objects to which the patient is exposed are not usually hazards.) A patient with chicken pox can transmit the disease from about two days before the appearance of the spots to the end of the blister stage, which lasts about five to seven days. Once dry scabs form, the disease is unlikely to spread. Most schools allow children with chicken pox back after ten days; some require children to stay home until the skin has completely cleared, although this is not necessary to prevent transmission. Direct exposure to shingles during the active phase when blisters have erupted but have not formed dry crusts can also cause chicken pox in people who have not yet had varicella. (A person with shingles cannot transmit the virus by breathing or coughing; it spreads only from the rash.)

Risk Factors for Shingles (Herpes Zoster)

Shingles occur in about 20% of those who have had chicken pox. An estimated 300,000 cases of shingles occur each year. The incidence of herpes zoster is almost 65% higher than it was 40 years. Although a person who has never been infected with varicella-zoster virus can catch chicken pox from exposure to shingles blisters, the opposite track is not possible; people cannot get herpes zoster from someone else with chicken pox. Shingles can only be a reactivation of an earlier varicella episode in the same person. Those at risk for such an occurrence are those whose immune systems are weakened or suppressed, usually from aging, immunodeficient diseases, or certain drugs. Skin injury may also cause a flare up in susceptible people.

Age. People over 60 years old have two to three times the risk for herpes zoster as those who are younger. One study reported that 30% of all cases occurs in people over 55, while less than 5% occur in those under fifteen. In people over 80, one in every 100 people has shingles. An Icelandic study reported, however, that it may be more common in children and adolescents than previously thought. In this study, 1.6 young people out of a 1,000 had herpes zoster -- a much higher rate in this age group than previously reported. The cases were generally mild, however, and had no recurrence.

Immunosuppression. People whose immune systems are impaired from diseases such as AIDS or a history of childhood cancer have a risk for herpes zoster that is multiples of those with healthy immune systems. Herpes zoster in people who are HIV positive may, in fact, be a sign of full-blown AIDS. The current drugs used for HIV -- protease inhibitors -- may also increase the risk for herpes zoster, although drug-associated herpes does not appear to be as severe as it usually is in AIDS patients.

Cancer. Cancer places people at risk for herpes zoster. At highest risk are those with Hodgkin's disease (13% to 15% of these patients develop shingles). About 7% to 9% of those with lymphomas and between 1% and 3% of patients with other cancers have herpes zoster. Chemotherapy itself increases the risk for herpes zoster.

Immunosuppressant Drugs. Patients are at risk for shingles (as well as other infections) who take certain drugs that suppress the immune system. They include cyclosporine (Sandimmune, Neoral), azathioprine (Imuran), cyclophosphamide (Cytoxan), chlorambucil (Leukeran), and cladribine. They are used often 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. They are also used for patients who have undergone organ transplantation.

How Serious Are Chicken Pox and Shingles?

People at High Risk for Complications of Chicken Pox and Shingles

Older People and Those with Compromised Immune Systems. People with suppressed immune systems, elderly people, and those with serious diseasesthe same groups that are at high risk for shinglesare also at risk for complications and recurrence of both chicken pox and shingles. (See Who Gets Chicken Pox and Shingles?, above.) The older the patient the higher the risk for complications from either variant of the VZV virus. People with suppressed immune systems from diseases, such as AIDS or leukemia, or immunosuppressive drugs are at the highest risk for severe forms and disseminated varicella-zoster (in which the infection spreads to internal organs).

Pregnant Women and Infants. Pregnant women who become infected with the varicella-zoster virus, whether in the form of chicken pox or shingles, are at increased risk for serious pneumonia.

Chicken pox in the mother during early pregnancy poses a slightly increased risk for birth defects in the infant, but it is not usually viewed as grounds for terminating a pregnancy. The highest risk, which occurs if the mother has chicken pox between the 13th and 20th week, is about 2%. Even in such cases, birth defects may be minor skin abnormalities; more serious ones include a smaller than normal head, eye problems, low birth weight, and mental retardation. (It should be noted that shingles in a pregnant woman does not appear to cause birth defects or pose a risk for infection in the infant.)

If women develop chicken pox (not shingles) within five days before and two days after delivery, their newborns are at risk for life-threatening varicella. Although chicken pox can still be very dangerous in older infants, most are protected by antibodies in breast milk from mothers who have had chicken pox. Nevertheless, all infants should have as little exposure to people with chicken pox as possible.

Complications of Chicken Pox (Varicella)

Almost all cases of chicken pox, particularly in children with normal health, cause no serious problems. Children who catch chicken pox from family members are likely to have a more severe case than if they caught it outside the home; but, even in such children, chicken pox is rarely serious. Complications occur in about one in a 1,000 cases of chicken pox, and the risk is higher in adolescents and adults and in those with other medical or immune problems. In children, boys have a higher risk for complications than girls. The condition is life-threatening only under rare and unusual circumstances; in a major analysis of 250,000 medical records, in fact, there were no deaths related to chicken pox. Except for itching, the complications described below are very rare, and parents should not be alarmed at all when their children develop this very common and nearly always mild disorder.

Recurrence and Reactivation. One episode of chicken pox nearly always confers life-long immunity against a second attack; such recurrence is possible but is very rare. Of course, the major long-term complication of varicella is the later reactivation of the herpes zoster virus and the development of shingles.

Itching. Itching, the most common complication of the varicella infection, can be very distressing, particularly for small children and their parents, although home remedies are available that can alleviate the discomfort (see How is Chicken Pox Treated?, 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, if the patient has scratched the spots, a secondary infection may develop at that site. Children with chicken pox are at much higher risk for this complication than adults are. The infection is usually caused by the bacteria Staphylococcus aureus or Streptococcus pyogenes. In such cases, permanent scarring may occur.

An outbreak of group A streptococcus was recently reported in a group of children who had chicken pox and attended a day care center. This bacteria is the cause of impetigo and strep throat. It is usually mild, but if it spreads in deep muscle, fat, or in the blood it can be life-threatening, causing such serious conditions as necrotizing fasciitis (the so-called flesh-eating bacteria) and toxic shock syndrome. A recent analysis indicated that streptococcus A is a greater problem than previously thought, although still very uncommon, occurring in only 22 out of 10,000 cases.

Effects on the Brain and Central Nervous System. Encephalitis, an infection in the brain, has occurred in a few varicella patients -- both children and adults. Fortunately, it is extremely rare. Symptoms vary; the patient may become over-agitated or may exhibit loss of coordination and poor balance. The condition can be very dangerous, causing coma and even death. One case of neurologic problems was reported in a child, two weeks after he had chicken pox, when he was given the drug desmopressin (DDAVP, Stimate) for bed-wetting. The relationship between the two events is unproven, but parents should be aware of the possible association and avoid the use of this drug in a child who has recently had chicken pox. Varicella-zoster associated cerebral vasculitis, in which blood vessels in the brain become inflamed, is a very rare cause of stroke in children.

Pneumonia. Adults and adolescents with chicken pox are at some risk for serious pneumonia, which should be suspected if coughing and abnormally rapid breathing develop. Pregnant women, smokers, and those with serious medical conditions have an even higher risk for pneumonia if they have chicken pox. Oxygen and intravenous acyclovir are key components for treating this condition. Pneumonia that is caused by varicella may result in lung scarring, which in turn can impair oxygen exchange over the following weeks or even months.

Disseminated Varicella. Disseminated varicella -- chicken pox that spreads to organ in the body -- is extremely serious and is a major problem for patients with compromised immune systems either as result of disease, inherited conditions, or certain drugs. For example, disseminated varicella occurs in up to 35% of children with chicken pox who are taking cancer chemotherapy; in such cases mortality rates are between 7% and 30%.

Reye's Syndrome. Reye's syndrome, a disorder that causes sudden and dangerous liver and brain damage, is a very rare complication of chicken pox and other viruses in children who take aspirin. 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, nearly nonexistent.

Other Rare Complications of Chicken Pox. Other extremely rare complications of varicella include problems in blood clotting and inflammation in the nerves in the hands and feet, and inflammation in other areas of the body, such as the heart, testicles, liver, joints, or kidney. Such cases of inflammation are nearly always temporary in otherwise healthy patients. Some children are at higher risk for ear infections from chicken pox. Hearing loss is a rare complication. There is some association between multiple sclerosis and herpes zoster although there is no evidence of a causal relationship.

Complications of Active Shingles

The pain and discomfort of the active infection can be intolerable for some shingles patients. About 14% of people with shingles develop complications within a month or two after the attack. The most common of these complications, postherpetic neuralgia, is discussed above (see What Are the Symptoms for Chicken Pox and Shingles?).

Recurrence. Shingles can recur, but the risk is low -- about the same as for an initial attack. There is some evidence that a first zoster episode boosts the immune system to ward off another attack. To support this, some elderly people with zoster who are exposed to children with chicken pox appear to have extra protection against a second zoster attack. (It should be noted that in people with impaired immune systems, such as those with AIDS, such a booster effect does not occur; these patients are at particular risk for multiple recurrences of shingles.)

Secondary Infection in the Blisters. If the blistered area is not kept clean and free from irritation, it may become infected, usually with Streptococcus A 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 herpes zoster and other viruses. The arms and legs become weak, painful, and, sometimes, even paralyzed. The trunk and face may be affected. Symptoms vary from being very mild to severe enough to require hospitalization. The disorder resolves in a few weeks to months. It should be noted that other viruses (e.g., C. jejuni, cytomegalovirus, and Epstein-Barr) are reported to have a stronger association to this syndrome than herpes zoster does. One study, in fact, found no higher incidence of herpes zoster virus in Guillain-Barre patients than in the general population.

Ramsay Hunt Syndrome. Ramsay Hunt syndrome (also called herpes zoster oticus) occurs when herpes zoster involves the nerves in the face and ears. It may cause severe ear pain and hearing loss, facial paralysis, loss of taste, and dizziness. It may also cause inflammation in the brain, which is usually mild. The dizziness may last for a few days or even for weeks but usually resolves. Severity of hearing loss varies from partial to total, but it, too, usually always goes away. Facial paralysis, on the other hand, may be permanent.

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 usually 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.

Infection 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 (called herpes zoster ophthalmicus), a severe infection can threaten vision. In AIDS patients, herpes zoster can cause a devastating infection in the retina called imminent acute retinal necrosis syndrome; prompt treatment with acyclovir can halt its progress. AIDS patients who have zoster may also be at risk for a chronic infection in the cornea of the eye.

Disseminated Herpes Zoster. As with disseminated chicken pox, herpes zoster that spreads to other organs can be serious to life-threatening. It may occur in 5% to 25% of immunocompromised patients, in whom the condition is fatal in 6% to 17% of cases. In very rare cases, herpes zoster has been associated with s- syndrome, an extensive and serious condition in which widespread blisters cover mucous membranes and large areas of the body.

What Tests Are Used to Detect Chicken Pox and Shingles?

Usually both chicken pox (varicella) and shingles (zoster) can be easily diagnosed using symptoms alone. Chicken pox, particularly in early stages, may be confused with herpes simplex, impetigo, insect bites, or scabies. Because the early prodrome stage of shingles can cause severe pain on one side of the lower back, chest, or abdomen before the rash appears, herpes zoster may be mistaken for disorders that cause acute pain in internal organs, such as gallstones. In the active rash stage, shingles is also sometimes confused with herpes simplex (the disorder commonly referred to simply as "herpes"). If a diagnosis is still unclear after a physical examination, then diagnostic tests may be required.

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 between one and fourteen days to detect the virus in the preparation made from the specimen. A culture is usually performed to distinguish between varicella zoster and herpes simplex viruses. 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.

Immunofluorescence

Immunofluorescence is a diagnostic technique used to identify antibodies to a specific disease -- in this case, 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. 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 particularly valuable for identifying infection in the central nervous system.

How Is Chicken Pox Treated?

Home Treatments

Acetaminophen. Patients with chicken pox do not have to stay in bed unless, of course, fever and flu symptoms are severe. To relieve discomfort, a child can take acetaminophen (Tylenol), with doses determined by the physician. A child should never be given aspirin or medications containing aspirin, which increase the risk for a dangerous condition called Reye's syndrome. (see How Serious Are Chicken Pox and Shingles?)

Soothing Baths. To relieve itching frequent baths are helpful, particularly 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 power. Use about two cups per bath; the oatmeal will not dissolve, and the water will look scummy. One-half to one cup of baking soda in a bath may also be helpful.

Lotions. Calamine lotion or similar over-the-counter preparations can be applied to the blisters to help dry them out and soothe the skin.

Antihistamines. For severe itching diphenhydramine (Benadryl) is useful and it also helps 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

Acyclovir is an anti-viral drug that may be used in adult varicella patients or those of any age with a high risk for complications and severity. The drug may also benefit smokers with chicken pox, who are at higher than normal risk for pneumonia. Some experts recommend its use for children who catch chicken pox from family members, because such patients are at risk for a 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 essential treatment for chicken pox pneumonia. (For a more detailed description of acyclovir and similar drugs, see Nucleoside Analogues, under How is Shingles Treated?, below.)

How Is Shingles Treated?

The treatment goals for active herpes zoster infection are to reduce pain and discomfort from zoster-associated pain, hasten healing of the blisters, and prevent the disease from spreading (disseminating). Therapies have been developed to fight the virus itself, although there is no cure for the disorder.

Home Treatments and Over-the-Counter Medications for Shingles

Applied Cold. Cold compresses soaked in Burrow's solution and cool baths may help relieve the blisters; it is important not to break them, which can cause infection. Experts advise against warm treatments, which can intensify itching. Patients should wear loose clothing and use clean loose gauze coverings over the affected areas.

Relief of Itching. In general, to prevent or reduce itching, home treatments are similar to those used for chicken pox. 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, such as acetaminophen or, in adults, aspirin, or other nonsteroidal anti-inflammatory drugs, such as ibuprofen (Advil). Such remedies, however, are usually not very effective for postherpetic neuralgia.

Medications for Severe Pain from Shingles or Postherpetic Neuralgia

Topical or Injected Substances. Capsaicin (Zostrix), which is available over the counter, is an ointment prepared from the active ingredient in hot chile peppers. This substance should not be used until the blisters have completely dried out and are falling off the skin. It should be applied using a glove three or four times daily. The patient will usually experience a burning sensation when the drug is first applied, but this sensation diminishes with use. Although it is approved for postherpetic neuralgia, its benefits are limited. In one study, it reduced pain by 21% compared to 6% in those who were given a placebo. It may take up to six weeks for the patient to experience its full effect, however, and about a third cannot tolerate the burning sensation. Many find no benefit.

Creams, patches, or gels containing the anesthetics lidocaine and prilocaine can be helpful, providing some relief within a day or two. Such treatments can be maintained while trying others, including drug therapies. Injections of anesthetics that block nerves can offer relief for some people. One study reported that a combination of a steroid (triamcinolone acetonide), lidocaine, and epinephrine given intravenously offered immediate relief for 24 out of 26 patients with postherpetic neuralgia. In all but one of the patients who experienced neuralgia immediately after a herpes outbreak, pain relief lasted at least 12 weeks. The long-term benefits of the treatment were far less in those who had chronic pain that was not triggered by herpes.

Other substances that may provide relief are ethyl chloride (Chloroethane) and Fluori-Methane, which are chemicals that cool the blood vessels in the skin. The spray is not an anesthetic but is used to inactivate the sensitive areas. The patient must be in a comfortable position and the face must be covered if the spray is being used near the head. The spray bottle is held upside-down about 12 to 18 inches from the targeted area.

Tricyclic Antidepressants. Tricyclic antidepressants help relieve several of the symptoms, including depression and pain, that affect herpes zoster sufferers with postherpetic neuralgia. They are now the standard treatments for PHN and relieve pain in up to 67% of patients. Two such drugs that have proven to be effective are amitriptyline (Elavil, Endep) and desipramine (Norpramin). Other tricyclics being tried include doxepin (Sinequan), imipramine (Tofranil), amoxapine (Asendin), and nortriptyline (Pamelor, Aventyl). It may take several weeks for the drugs to become fully effective. Elderly people are at higher risk for certain side effects of tricyclic antidepressants, such as dry mouth, blurred vision, difficulty in urinating, constipation, disturbances in heart rhythm, and dizziness. The drugs can also cause an abrupt drop in blood pressure when standing up. Desipramine may have fewer of these problems than amitriptyline.

Antiseizure Drugs. Gabapentin (Neurontin), carbamazepine (Tegretol), valproic acid (Depakene, Depakote), and phenytoin (Dilantin) are anti-seizure drugs. They appear to help PHN patients who have episodes of searing or tearing pain. Gabapentin -- unlike other anti-seizure medications -- may have some effect on persistent pain. Some experts now recommend gabapentin as a first-line drug against PHN. Side effects include skin rashes, increased risk for infection, headache, sleepiness, and upset stomach. Some people experience visual disturbances, ringing in the ears, agitation, or odd movements when drug levels are at their peak.

Opioids. In patients with severe pain that does not respond to tricyclic antidepressants, more powerful pain-killing opioid drugs may be needed. Oxycodone is most often tried first. Although there is some concern that drug dependency may develop, studies indicate that if these narcotics are carefully monitored, they remain effective and the risk for addiction is very low.

Corticosteroids. Corticosteroids, including prednisolone or prednisone, are powerful anti-inflammatory medications, and some experts hoped they would reduce the nerve inflammation that causes zoster pain. They have some benefit for reducing pain in acute attacks, but have little or no value for preventing or treating postherpetic neuralgia. In general, corticosteroids are used in combination with or have been replaced by anti-virus drugs, such as acyclovir (see below). Because they actually suppress infection, some experts are concerned that they may reactivate virus-related complications. Some experts believe, in fact, that corticosteroids should only be taken with anti-viral drugs, if at all. Side effects of corticosteroids can be severe and they should be taken at as low a dose and for as short a time as possible. They should be taken with caution or not all by people with impaired immune systems, osteoporosis, diabetes mellitus, hypertension, or a number of other conditions common in older adults.

Experimental Drugs. Drugs are being developed that block certain receptors in the spinal cord called N-methyl-d aspartate (NMDA). These receptors bind with amino acids called aspartate and glutamate, which are released when nerves are injured and increase sensitivity and pain perception. Animal tests using NMDA-antagonist drugs are showing promise.

Dextromethorphan is an active ingredient in a number of common over-the-counter medications, including Pertussin, Benyulin, Robitussin, Vicks Formula 44, and others. It is related to morphine but is not a narcotic. Currently, it is being tested in patients with PHN for its effects on abnormal central nervous system processing.

Antiviral Drugs

Nucleoside Analogues. The best class of drugs developed against varicella-zoster are those known as nucleoside analogues, which are able to block viral reproduction. Because herpes zoster tends to resolve fairly quickly in young adults, these drugs are generally used in severe cases of patients who are susceptible to complications, including elderly people and those whose eyes are endangered by the infection. Acyclovir (Zovirax), famciclovir (Famvir), and valaciclovir (Valtrex) have now been approved for shingles. Most of these drugs appear to have little or no harmful effect on healthy cells and can penetrate most body tissues, including cerebrospinal fluid. Each of these drugs is usually taken for seven days. If taken within 72 hours of the onset of infection, they can significantly reduce symptoms, although none can actually destroy the virus and cure the disease.

Acyclovir is the most common of these drugs, but it must be taken orally five times a day at 800 mg per dose, so compliance is often low. Studies have reported that taking a corticosteroid with acyclovir for three weeks significantly reduced symptoms and hastened healing compared to using either drug alone. Combinations with corticosteroids have no added effect on persistent pain or PHN. Although individual studies using acyclovir alone have not reported any protection against developing postherpetic neuralgia, one analysis of results from four studies suggested that the drug reduced the incidence of PHN by nearly half.

Famciclovir (Famvir) and valaciclovir (Valtrex) are metabolized by the body into acyclovir. These newer drugs appear to be as safe as acyclovir and have the advantage of better absorption and slower metabolism. Therefore, they require fewer doses (three per day) compared to acyclovir's five doses a day. Famciclovir and valaciclovir remain active in the infected cells longer than acyclovir and may have some additional advantage for treating postherpetic neuralgia. One study found that famciclovir reduced the duration of PHN by two months. Another study found that valaciclovir was more effective in reducing zoster pain and fewer patients had pain that persisted for six months compared to those taking acyclovir. Other nucleoside analogues that are sometimes used include penciclovir (Denavir) and idoxuridine (Herplex, Stoxil, Virexen), which is used only as a skin cream or ointment. Another anti-viral drug under investigation is bromodeoxyuridine (BVDU, Brivudin).

Possible side effects of all nucleoside analogues include nausea and vomiting, rash, headache, fatigue, tremor, and, very rarely, seizures. Complications of intravenous administration, which is used for AIDS and other immunocompromised patients, include an increased risk for kidney damage and blood clots at the injection site

Anti-Viral Drugs for Patients with Impaired Immune Systems. Nucleoside analogues and similar anti-viral drugs are very important for herpes zoster patients who have impaired immune systems. In studies of AIDS patients with recurrent herpes zoster, acyclovir has reduced the mortality rate and the spread of herpes to internal organs. The drugs sorivudine (Bravavir), or BV-araU, and fiacitabine are very powerful anti-viral drugs known as a synthetic pyrimidine analogue. They are being investigated for treating HIV patients with herpes zoster. It should be noted, however, that although sorivudine is proving to be more effective than acyclovir, it is unlikely to be approved after reports of lethal interactions with the chemotherapeutic drug 5-fluorouracil (5-FU).

Alternative treatments for people with impaired immune systems are intravenous administration of vidarabine (Vira-A, Ara-A) or interferon alpha. Interferons are virus*fighting proteins produced by genetic engineering. Intravenous foscarnet (Foscavir) is being used for patients with impaired immune systems who have developed resistance to acyclovir. In such cases, toxicity from the drug combinations can be lethal.

Non-Drug Techniques

Stress Reduction Techniques. Recently, a panel of experts concluded that a number of relaxation and stress-reduction techniques were helpful in managing chronic pain. They include meditation, deep breathing exercises, biofeedback, and muscle relaxation. Such techniques may apply to those with severe pain from acute infection and from persistent long-term postherpetic neuralgia. Biofeedback, for example, is a method that trains patients to relax using a signal. During biofeedback, electric leads are taped to a subject's head. The person is encouraged to relax using standard relaxation techniques, such as deep breathing or muscle relaxation. Brains waves are measured and an auditory signal is emitted when alpha waves are detected, a frequency that coincides with a state of deep relaxation. By repeating the process, subjects associate the sound with the relaxed state and learn to achieve relaxation by themselves.

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 only one negative and, to a degree, a manageable experience among many positive ones. Cognitive therapy may be expensive and often not covered by insurance. The skill of the therapist is very important to its success.

Transcutaneous Electrical Nerve Stimulation. Transcutaneous electric nerve stimulation (TENS) uses low-level electrical pulses to suppress pain in specific areas. The standard approach is to give 80 to 100 pulses per second for 45 minutes three times a day; patients are barely aware of the sensation. In small studies, this technique provided partial to complete relief for some PHN patients.

Surgical Techniques. Certain surgical techniques in the brain or spinal cord have been used to block pain centers contributing to 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.

Alternative Treatments

There are some reports that hypnosis may be useful for alleviating pain. Although acupuncture is becoming increasingly popular for a number of painful conditions, one study reported that it offered no benefits for postherpetic neuralgia. Patients with chronic pain should be very wary of herbal or so-called natural remedies. It is extremely important for patients to realize that herbal medicine has as many potential side effects and toxic reactions as standard drug therapy, and the dangers increase because no standards exist for safe or effective dosages. For example, three women developed acute hepatitis from Jin Bu Huan, a Chinese herbal remedy sold as treatment for pain and insomnia. Everyone is strongly advised to consult a physician before using any untested products. The Food and Drug Administration now has a program called MEDWATCH for people to report adverse reactions to untested substances, such as herbal remedies and vitamins (call 800-332-1088).

How Can Chicken Pox and Shingles Be Prevented?

Varicella-Zoster Immune Globulin

Varicella-zoster immune globulin (VZIG) is a substance that triggers an immune response against the varicella-zoster virus. It is used to protect high-risk patients who are exposed to chicken pox or those who cannot receive a vaccination of the live virus. Such groups include pregnant women with no history of chicken pox; newborns under four weeks who are exposed to chicken pox or shingles; premature infants; symptomatic HIV-positive patients with no antibodies to VZV; recipients of bone-marrow transplants (even if they have had chicken pox); and patients with a debilitating disease even if they have had chicken pox. VZIG should be given within 96 hours of exposure and no later than 10 days

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