chickenpox

(chĭk'ən-pŏks')

[Perhaps in allusion to the mildness of the disease as contrasted with smallpox.]

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Definition

Chickenpox (also called varicella) is a common, extremely infectious, rash-producing childhood disease that also affects adults on occasion.

Description

Chickenpox is caused by the varicella-zoster virus (a member of the herpes virus family), which is spread through the air or by direct contact with an infected person. It produces an itchy, blistery rash that typically lasts about a week and is sometimes accompanied by a fever or other symptoms. A single attack of chickenpox almost always brings lifelong immunity against the disease. Because the symptoms of chickenpox are easily recognized and in most cases merely unpleasant rather than dangerous, treatment can almost always be carried out at home. Severe complications can develop, however, and professional medical attention is essential in some circumstances.

Once someone has been infected with the virus, an incubation period of about 10 to 21 days passes before symptoms begin. The period during which infected people are able to spread the disease is believed to start one or two days before the rash breaks out and to continue until all the blisters have formed scabs, which usually happens four to seven days after the rash breaks out but may be longer in adolescents and adults. For this reason, doctors recommend keeping children with chickenpox away from school for about a week. It is not necessary, however, to wait until all the scabs have fallen off.

Prior to the use of the varicella vaccine, chickenpox was a typical part of growing up for most children in the industrialized world. The disease can strike at any age, but throughout the twentieth century by ages nine or ten about 80 to 90 percent of American children had already been infected. U.S. children living in rural areas and many foreign-born children were less likely to be immune. Study results reported by the Centers for Disease Control and Prevention (CDC) indicate that more than 90 percent of American adults are immune to the chickenpox virus. Adults, however, are much more likely than children to suffer dangerous complications. More than half of all chickenpox deaths occur among adults.

Demographics

Before the varicella vaccine (Varivax) was released for use in 1995, nearly all of the 4 million children born each year in the United States contracted chickenpox, resulting in hospitalization in five of every 1,000 cases and 100 deaths. Because almost every case of chickenpox, no matter how mild, leads to lifelong protection against further attacks, adults account for less than 5 percent of all cases in the United States.

Causes and Symptoms

A case of chickenpox usually starts without warning or with only a mild fever and a slight feeling of unwellness. Within a few hours or days small red spots begin to appear on the scalp, neck, or upper half of the trunk. After another 12 to 24 hours the spots typically become itchy, fluid-filled bumps called vesicles, which continue to appear in crops for the next two to five days. In any area of skin, lesions of a variety of stages can be seen. These blisters can spread to cover much of the skin, and in some cases also may be found inside the mouth, nose, ears, vagina, or rectum. Some people develop only a few blisters, but in most cases the number reaches 250 to 500. The blisters soon begin to form scabs and fall off. Scarring usually does not occur unless the blisters have been scratched and become infected. Occasionally a minor and temporary darkening of the skin (called hyperpigmentation) is noticed around some of the blisters. The degree of itchiness can range from barely noticeable to extreme. Some chickenpox sufferers also have headaches, abdominal pain, or a fever. Full recovery usually takes five to ten days after the first symptoms appear. Again, the most severe cases of the disease tend to be found among older children and adults.

Although for most people chickenpox is no more than a matter of a few days' discomfort, some groups are at risk for developing complications, the most common of which are bacterial infections of the blisters, pneumonia, dehydration, encephalitis, and hepatitis. Some of the groups at greater risk are:

• Infants: Complications occur much more often among children younger than one year old than among older children. The threat is greatest to newborns, who are more at risk of death from chickenpox than any other group. Under certain circumstances, children born to mothers who contract chickenpox just prior to delivery face an increased possibility of dangerous consequences, including brain damage and death. If the infection occurs during early pregnancy, there is a small (less than 5%) risk of congenital abnormalities.
• Immunocompromised children: Children whose immune systems have been weakened by a genetic disorder, disease, or medical treatment usually experience the most severe symptoms of any group. They have the second-highest rate of death from chickenpox.
• Adults and children 15 and older: Among this group, the typical symptoms of chickenpox tend to strike with greater force, and the risk of complications is much higher than among young children.

Immediate medical help should always be sought when anyone in these high-risk groups contracts the disease.

Diagnosis

Where children are concerned, especially those with recent exposure to the disease, diagnosis can usually be made at home, by a school nurse, or by a doctor over the telephone if the child's parent or caregiver is unsure that the disease is chickenpox.

Treatment

With children, treatment usually takes place in the home and focuses on reducing discomfort and fever. Because chickenpox is a viral disease, antibiotics are ineffective against it.

Applying wet compresses or bathing the child in cool or lukewarm water once a day can help the itch. Adding four to eight ounces of baking soda or one or two cups of oatmeal to the bath is a good idea (oatmeal bath packets are sold by pharmacies). Only mild soap should be used in the bath. Patting, not rubbing, is recommended for drying the child off, to prevent irritating the blisters. Calamine lotion (and some other kinds of lotions) also reduces itchiness. Because scratching can cause blisters to become infected and lead to scarring, the child's nails should be cut short. Of course, older children need to be warned not to scratch. For babies, light mittens or socks on the hands can help guard against scratching.

If mouth blisters make eating or drinking an unpleasant experience, cold drinks and soft, bland foods can ease the child's discomfort. Painful genital blisters can be treated with an anesthetic cream recommended by a doctor or pharmacist. Antibiotics often are prescribed if blisters become infected.

Fever and discomfort can be reduced by acetaminophen or another medication that does not contain aspirin. Aspirin and any medications that contain aspirin or other salicylates must not be used with chickenpox, for they appear to increase the chances of developing Reye's syndrome. The best idea is for a parent to consult a doctor or pharmacist to confirm which medications are safe.

Immunocompromised chickenpox sufferers are sometimes given an antiviral drug called acyclovir (Zovirax). Studies have shown that Zovirax also lessens the symptoms of otherwise healthy children and adults who contract chickenpox, but the notion that it should be used to treat the disease among the general population, especially in children, is controversial.

Prognosis

Most cases of chickenpox run their course within a week without causing lasting harm. However, there is one long-term consequence of chickenpox that strikes about 20 percent of the population, particularly people 50 and older. Like all herpes viruses, the varicella-zoster virus never leaves the body after an episode of chickenpox. It lies dormant in the nerve cells, where it may be reactivated years later by disease or age-related weakening of the immune system. The result is shingles (also called herpes zoster), a painful nerve inflammation, accompanied by a rash that usually affects the trunk or the face for ten days or more. Especially in the elderly, pain, called postherpetic neuralgia, may persist at the site of the shingles for months or years. As of 2004, two relatively newer drugs for treatment of shingles are valacyclovir (Valtrex) and famciclovir (Famvir), both of which stop the replication of herpes zoster when administered within 72 hours of appearance of the rash. The effectiveness of these two drugs in immunocompromised patients has not been established, and Famvir was not recommended for patients under 18 years.

Prevention

A substance known as varicella-zoster immune globulin (VZIG), which reduces the severity of chickenpox symptoms, is as of 2004 available to treat immunocompromised children and others at high risk of developing complications. It is administered by injection within 96 hours of known or suspected exposure to the disease and is not useful after that. VZIG is produced as a gamma globulin from blood of recently infected individuals.

A vaccine for chickenpox became available in the United States in 1995 under the name Varivax. Varivax is a live, attenuated (weakened) virus vaccine. It has been proven to be 85 percent effective for preventing all cases of chickenpox and close to 100 percent effective in preventing severe cases. Side effects are normally limited to occasional soreness or redness at the injection site. CDC guidelines state that the vaccine should be given to all children (with the exception of certain high-risk groups) at 12 to 18 months of age, preferably when they receive their measles-mumps-rubella vaccine. For older children, up to age 12, the CDC recommends vaccination when a reliable determination that the child in question has already had chickenpox cannot be made. Vaccination also is recommended for any older child or adult considered susceptible to the disease, particularly those, such as healthcare workers and women of childbearing age, who face a greater likelihood of severe illness or transmitting infection. A single dose of the vaccine was once thought sufficient for children up to age 12; older children and adults received a second dose four to eight weeks later. However, an outbreak at a daycare center in 2000 brought concern in the medical community about a second vaccination for younger children, since many of the affected children had been vaccinated. Researchers began recommending a second vaccination in 2002. In 1997, the cost of two adult doses of the vaccine in the United States was about $80. Although this cost was not always covered by health insurance plans, children up to age 18 without access to the appropriate coverage could be vaccinated free of charge through the federal Vaccines for Children program. Varivax is not given to patients who already have overt signs of the disease. It was once thought unsafe for children with chronic kidney disease, but a 2003 report said the vaccination was safe in these children. The finding is important, since even chickenpox can be a serious complication in children who must undergo a kidney transplant.

The vaccine also is not recommended for pregnant women, and women should delay pregnancy for three months following a complete vaccination. The vaccine is useful when given early after exposure to chickenpox and, if given in the midst of the incubation period, it can be preventative. The Infectious Diseases Society of America stated in 2000 that immunization is recommended for all adults who have never had chickenpox.

While there was initial concern regarding the vaccine's safety and effectiveness when first released, the vaccination is in the early 2000s gaining acceptance as numerous states require it for admittance into daycare or public school. In 2000, 59 percent of toddlers in the United States were immunized; up from 43.2 percent in 1998. A study published in 2001 indicates that the varicella vaccine is highly effective when used in clinical practice. Although evidence has not ruled out a booster shot later in life, all research addressing the vaccine's effectiveness throughout its six-year use indicates that chickenpox may be the first human herpes virus to be wiped out. Although initial concerns questioned if the vaccination might make shingles more likely, studies are beginning in the early 2000s to show the effectiveness of the vaccine in reducing cases of that disease.

Parental Concerns

A doctor should be called immediately if any of the following occur:

• The child's fever goes above 102°F (38.9°C) or takes more than four days to disappear.
• The child's blisters appear infected. Signs of infection include leakage of pus from the blisters or excessive redness, warmth, tenderness, or swelling around the blisters.
• The child seems nervous, confused, unresponsive, or unusually sleepy; complains of a stiff neck or severe headache; shows signs of poor balance or has trouble walking; finds bright lights hard to look at; is having breathing problems or is coughing a lot; is complaining of chest pain; is vomiting repeatedly; or is having convulsions. These may be signs of Reye's syndrome or encephalitis, two rare but potentially dangerous conditions.

Resources

Books

Arvin, Ann M. "Varicella-zoster Virus." In Principles and Practice of Pediatric Infectious Diseases, 2nd ed. Edited by Sarah S. Long et al. St. Louis, MO: Elsevier, 2003.

Myers, Martin G., et al. "Varicella-Zoster Virus." In Nelson Textbook of Pediatrics. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2004.

Periodicals

Arvin, Ann M. "Varicella Vaccine: The First Six Years." New England Journal of Medicine (March 2001).

"Chickenpox Vaccine OK for Pediatric Patients." Vaccine Weekly (January 22, 2003): 25.

Henderson, C. W. "Chickenpox Immunization Confirmed Effective in Adults." Vaccine Weekly (September 2000): 22.

"Study: Two Vaccines Work Best." Vaccine Weekly (January 8, 2003): 14.

Organizations

Centers for Disease Control and Prevention. 1600 Clifton Rd., NE, Atlanta, GA 30333. Web site: www.cdc.gov.

Web Sites

"Chickenpox." MedlinePlus. Available online at www.nlm.nih.gov/medlineplus/chickenpox.html (accessed December 25, 2004).

[Article by: Beth A. Kapes Teresa G. Odle Rosalyn Carson-DeWitt, MD]

Chicken pox (varicella) is a highly infectious, acute viral illness caused by the varicella zoster virus. The illness is characterized by a generalized pruritic, vesicular rash with fever and systemic symptoms usually lasting from seven to ten days. In the pre-immunization era in the United States, there were approximately 4 million cases, 11,000 hospitalizations, and 100 deaths every year. Most cases occurred in children under ten years of age. Complications from chicken pox include pneumonia, encephalitis, cerebellar ataxia, infections, and bleeding disorders. Infants, adults, and immunocompromised persons are at higher risk of severe disease, hospitalization, and death.

Once a person recovers from chicken pox, the virus stays in the body for life (becomes latent), residing in nerve cells known as dorsal root ganglia. The virus can reactivate, resulting in herpes zoster (shingles), which usually presents as a band-like rash in an area of the body that receives innervation from one sensory nerve. Approximately 15 percent of persons who have had chicken pox will develop shingles at some point in their lives, the risk increasing with advancing age. Most cases are associated with a vesicular rash, though some affected persons experience local pain as well. However, persons older than fifty years may develop a severe pain syndrome lasting for months known as post-herpetic neuralgia.

In 1995, a live, attenuated vaccine was licensed in the United States for routine childhood immunization against chicken pox. Since then, the number of cases of chicken pox has decreased significantly. Another vaccine has been tested for prevention or modification of shingles.

(SEE ALSO: Communicable Disease Control; Immunizations)

— KARIN GALIL; JANE SEWARD

A mild but highly contagious disease, caused by a virus and characterized by slight fever and the eruption of blisters on the skin. Chicken pox is classified as a disease of childhood, although it can occur in adults.

(chickenpox), an acute communicable disease with an incubation period of 2 or 3 weeks and caused by herpesvirus, usually found in children. Manifestations include coryza, fever, malaise, and headache, followed in 2 or 3 days by the eruption of macular vesicles.

Varicella. (Regezi/Sciubba/Jordan, 2003)

• Diseases and Infestations - chickenpox: mild, highly infectious viral disease primarily in children with itchy rash of red pimples, blisters, and pustules; varicella

For other uses, see Chickenpox (disambiguation).

"Varicella" redirects here. For other uses, see Varicella (disambiguation).

Chickenpox
Classification and external resources
Child with varicella disease
ICD-10	B01
ICD-9	052
DiseasesDB	29118
MedlinePlus	001592
eMedicine	ped/2385 derm/74, emerg/367
MeSH	C02.256.466.175

Chickenpox or chicken pox is a highly contagious illness caused by primary infection with varicella zoster virus (VZV).^[1] It usually starts with vesicular skin rash mainly on the body and head rather than at the periphery and becomes itchy, raw pockmarks, which mostly heal without scarring. On examination, the observer typically finds lesions at various stages of healing.

Chickenpox is an airborne disease spread easily through coughing or sneezing of ill individuals or through direct contact with secretions from the rash. A person with chickenpox is infectious one to two days before the rash appears.^[2] They remain contagious until all lesions have crusted over (this takes approximately six days)^[3]. Immunocompromised patients are contagious during the entire period as new lesions keep appearing. Crusted lesions are not contagious.^[4]

It takes from 10 to 21 days after initial infection for the disease to develop.

The onset of illness with chickenpox is often characterized by symptoms including myalgia, itching, nausea, fever, headache, sore throat, pain in both ears, complaints of pressure in head or swollen face, and malaise in adolescents and adults. In children, the first symptom is usually the development of a papular rash, followed by development of malaise, fever (a body temperature of 38 °C (100 °F), but may be as high as 42 °C (108 °F) in rare cases), sometimes severe back pains to the lower back, and anorexia (loss of appetite, not to be confused with anorexia nervosa). Typically, the disease is more severe in adults.^[5] Chickenpox is rarely fatal, although it is generally more severe in adult males than in adult females or children. Non-immune pregnant women and those with a suppressed immune system are at highest risk of serious complications. Chickenpox is believed to be the cause of one third of stroke cases in children.^[6] The most common late complication of chickenpox is shingles, caused by reactivation of the varicella zoster virus decades after the initial episode of chickenpox.

Chickenpox has been observed in other primates, including chimpanzees^[7] and gorillas.^[8]

Contents 1 Diagnosis 2 Epidemiology 3 Pathophysiology 3.1 Infection in pregnancy and neonates 3.2 Shingles 4 Prevention 4.1 Hygiene measures 4.2 Vaccine 5 Treatment 5.1 Children 5.2 Adults 6 Prognosis 7 See also 8 References 9 External links

Diagnosis

The diagnosis of varicella is primarily clinical, with typical early "prodromal" symptoms, and then the characteristic rash. Confirmation of the diagnosis can be sought through either examination of the fluid within the vesicles of the rash, or by testing blood for evidence of an acute immunologic response.

Vesicular fluid can be examined with a Tsanck smear, or better with examination for direct fluorescent antibody. The fluid can also be "cultured", whereby attempts are made to grow the virus from a fluid sample. Blood tests can be used to identify a response to acute infection (IgM) or previous infection and subsequent immunity (IgG).^[9]

Prenatal diagnosis of fetal varicella infection can be performed using ultrasound, though a delay of 5 weeks following primary maternal infection is advised. A PCR (DNA) test of the mother's amniotic fluid can also be performed, though the risk of spontaneous abortion due to the amniocentesis procedure is higher than the risk of the baby developing fetal varicella syndrome.^[10]

Epidemiology

Primary varicella is a disease that is endemic to all countries worldwide. Varicella has a prevalence that is stable from generation to generation.^[11]

In temperate countries, chickenpox is primarily a disease of children, with most cases occurring during the winter and spring, most likely due to school contact. It is one of the classic diseases of childhood, with the highest prevalence in the 4–10 year old age group. Like rubella, it is uncommon in preschool children. Varicella is highly communicable, with an infection rate of 90% in close contacts. In temperate countries, most people become infected before adulthood but 10% of young adults remain susceptible.

In the tropics, chickenpox often occurs in older people and may cause more serious disease.^[12] In adults the pock marks are darker and the scars more prominent than in children.^[13]

Pathophysiology

A single blister, typical during the early stages of the rash

The back of a 30-year-old male, on day 5 of the rash

Exposure to VZV in a healthy child initiates the production of host immunoglobulin G (IgG), immunoglobulin M (IgM), and immunoglobulin A (IgA) antibodies; IgG antibodies persist for life and confer immunity. Cell-mediated immune responses are also important in limiting the scope and the duration of primary varicella infection. After primary infection, VZV is hypothesized to spread from mucosal and epidermal lesions to local sensory nerves. VZV then remains latent in the dorsal ganglion cells of the sensory nerves. Reactivation of VZV results in the clinically distinct syndrome of herpes zoster (i.e., shingles), postherpetic neuralgia, and sometimes Ramsay Hunt syndrome type II.^{[citation needed]}

Infection in pregnancy and neonates

For pregnant women, antibodies produced as a result of immunization or previous infection are transferred via the placenta to the fetus.^[14] Women who are immune to chickenpox cannot become infected and do not need to be concerned about it for themselves or their infant during pregnancy.^[15]

Varicella infection in pregnant women could lead to viral transmission via the placenta and infection of the fetus. If infection occurs during the first 28 weeks of gestation, this can lead to fetal varicella syndrome (also known as congenital varicella syndrome).^[16] Effects on the fetus can range in severity from underdeveloped toes and fingers to severe anal and bladder malformation. Possible problems include:

• Damage to brain: encephalitis,^[17] microcephaly, hydrocephaly, aplasia of brain
• Damage to the eye: optic stalk, optic cup, and lens vesicles, microphthalmia, cataracts, chorioretinitis, optic atrophy
• Other neurological disorder: damage to cervical and lumbosacral spinal cord, motor/sensory deficits, absent deep tendon reflexes, anisocoria/Horner's syndrome
• Damage to body: hypoplasia of upper/lower extremities, anal and bladder sphincter dysfunction
• Skin disorders: (cicatricial) skin lesions, hypopigmentation

Infection late in gestation or immediately following birth is referred to as "neonatal varicella".^[18] Maternal infection is associated with premature delivery. The risk of the baby developing the disease is greatest following exposure to infection in the period 7 days prior to delivery and up to 7 days following the birth. The baby may also be exposed to the virus via infectious siblings or other contacts, but this is of less concern if the mother is immune. Newborns who develop symptoms are at a high risk of pneumonia and other serious complications of the disease.^[10]

Shingles

Main article: Herpes zoster

After a chickenpox infection, the virus remains dormant in the body's nerve tissues. The immune system keeps the virus at bay, but later in life, usually as an adult, it can be reactivated and cause a different form of the viral infection called shingles (scientifically known as herpes zoster).^[19]

Many adults who have had chicken pox as children are susceptible to shingles as adults, often with the accompanying condition postherpetic neuralgia, a painful condition that make it difficult to sleep. Even after the shingles rash has gone away, there can be night pain in the area affected by the rash.^[20]

Shingles affect one in three adults, especially those who are immune suppressed, particularly from cancer, HIV, or other conditions. However, stress can bring on shingles as well, although scientists are still researching the connection. ^[21]

A shingles vaccine is available for adults over 50 for both adults who had childhood chickenpox or who previously had shingles. ^[22] The vaccine for shingles lessens the impact of shingles and its side effects.

Prevention

Hygiene measures

The spread of chickenpox can be prevented by isolating affected individuals. Contagion is by exposure to respiratory droplets, or direct contact with lesions, within a period lasting from three days prior to the onset of the rash, to four days after the onset of the rash.^[23] The chickenpox virus (VZV) is susceptible to disinfectants, notably chlorine bleach (i.e., sodium hypochlorite). Also, like all enveloped viruses, VZV is sensitive to desiccation, heat and detergents. Therefore these viruses are relatively easy to kill.^{[citation needed]}

Vaccine

Main article: Varicella vaccine

A varicella vaccine was first developed by Michiaki Takahashi in 1974 derived from the Oka strain. It has been available in the U.S. since 1995 to inoculate against the disease. Some countries require the varicella vaccination or an exemption before entering elementary school. Protection from one dose is not lifelong and a second dose is necessary five years after the initial immunization,^[24] which is currently part of the routine immunization schedule in the US.^[25] The chickenpox vaccine is not part of the routine childhood vaccination schedule in the UK. In the UK, the vaccine is currently only offered to people who are particularly vulnerable to chickenpox. A person who already took the vaccine is more likely to have only a few chickenpox.^[26]

Treatment

Varicella treatment mainly consists of easing the symptoms as there is no actual cure of the condition. Some treatments are however available for relieving the symptoms while the immune system clears the virus from the body. As a protective measure, patients are usually required to stay at home while they are infectious to avoid spreading the disease to others. Also, sufferers are frequently asked to cut their nails short or to wear gloves to prevent scratching and to minimize the risk of secondary infections.

The condition resolves by itself within a couple of weeks but meanwhile patients must pay attention to their personal hygiene.^[27] The rash caused by varicella zoster virus may however last for up to one month, although the infectious stage does not take longer than a week or two.^[28] Also, staying in a cold surrounding can help in easing the itching as heat and sweat makes it worse.

Although there have been no formal clinical studies evaluating the effectiveness of topical application of calamine lotion, a topical barrier preparation containing zinc oxide and one of the most commonly used interventions, it has an excellent safety profile.^[29] It is important to maintain good hygiene and daily cleaning of skin with warm water to avoid secondary bacterial infection.^[30] Scratching may also increase the risk of secondary infection.^[31]

To relieve the symptoms of chickenpox, people commonly use anti-itching creams and lotions. These lotions are not to be used on the face or close to the eyes. Neem leaves can be made into paste form and can be applied on the rashes. Warm water bath with neem leaves may be helpful. Water bath may be done at least seven days from the onset of the vesicles. It should be done so because the vesicles contains the virus and may splash while bathing and it may cause the vesicles to appear on subsequent regions. An oatmeal bath also might help ease discomfort.^[32]

Children

If oral acyclovir is started within 24 hours of rash onset it decreases symptoms by one day but has no effect on complication rates. Use of acyclovir therefore is not currently recommended for immunocompetent individuals (i.e., otherwise healthy persons without known immunodeficiency or on immunosuppressive medication). Children younger than 12 years old and older than one month are not meant to receive antiviral medication if they are not suffering from another medical condition which would put them at risk of developing complications.^[33]

Treatment of chickenpox in children is aimed at symptoms whilst the immune system deals with the virus. With children younger than 12 years cutting nails and keeping them clean is an important part of treatment as they are more likely to deep scratch their blisters.^[34]

Aspirin is highly contraindicated in children younger than 16 years as it has been related with a potentially fatal condition known as Reye's syndrome.^[35]

Some parents believe that it is better for children to contact chickenpox than get the vaccine. They even go the extent of exposing their children to others who have the disease – even by taking them to "chicken pox parties." Doctors counter that children are safer getting the vaccine, which is weakened form of the virus, than by getting the disease, which can be fatal.^[36]

Adults

Infection in otherwise healthy adults tends to be more severe and may be fatal. Treatment with antiviral drugs (e.g. acyclovir or valacyclovir) is generally advised, as long as it is started within 24–48 hours from rash onset.^[33] Remedies to ease the symptoms of chickenpox in adults are basically the same as those used on children. Adults are more often prescribed antiviral medication as it is effective in reducing the severity of the condition and the likelihood of developing complications. Antiviral medicines do not kill the virus, but stop it from multiplying. Adults are also advised to increase water intake to reduce dehydration and to relieve headaches. Painkillers such as paracetamol (acetaminophen) are also recommended as they are effective in relieving itching and other symptoms such as fever or pains. Antihistamines relieve itch and may be used in cases where the itch prevents sleep, because they are also sedative. As with children, antiviral medication is considered more useful for those adults who are more prone to develop complications. These include pregnant women or people who have a weakened immune system.^[37]

Sorivudine, a nucleoside analogue has been reported to be effective in the treatment of primary varicella in healthy adults (case reports only), but large-scale clinical trials are still needed to demonstrate its efficacy.^[38]

Prognosis

The duration of the visible blistering caused by varicella zoster virus varies in children usually from 4 to 7 days, and the appearance of new blisters begins to subside after the 5th day. Chickenpox infection is milder in young children, and symptomatic treatment, with sodium bicarbonate baths or antihistamine medication may ease itching.^[39] Paracetamol (acetaminophen) is widely used to reduce fever. Aspirin, or products containing aspirin, should not be given to children with chickenpox as it can cause Reye's Syndrome.^[40]

In adults, the disease is more severe,^[41] though the incidence is much less common. Infection in adults is associated with greater morbidity and mortality due to pneumonia,^[42] hepatitis, and encephalitis.^{[citation needed]} In particular, up to 10% of pregnant women with chickenpox develop pneumonia, the severity of which increases with onset later in gestation. In England and Wales, 75% of deaths due to chickenpox are in adults.^[10] Inflammation of the brain, or encephalitis, can occur in immunocompromised individuals, although the risk is higher with herpes zoster.^[43] Necrotizing fasciitis is also a rare complication.^[44]

Varicella can be lethal to adults with impaired immunity. The number of people in this high-risk group has increased, due to the HIV epidemic and the increased use immunosuppressive therapies.^[45] Varicella is a particular problem in hospitals, especially when there are patients with immune systems weakened by drugs (e.g., high-dose steroids) or HIV.^[46]

Secondary bacterial infection of skin lesions, manifesting as impetigo, cellulitis, and erysipelas, is the most common complication in healthy children. Disseminated primary varicella infection usually seen in the immunocompromised may have high morbidity. Ninety percent of cases of varicella pneumonia occur in the adult population. Rarer complications of disseminated chickenpox also include myocarditis, hepatitis, and glomerulonephritis.^[47]

Hemorrhagic complications are more common in the immunocompromised or immunosuppressed populations, although healthy children and adults have been affected. Five major clinical syndromes have been described: febrile purpura, malignant chickenpox with purpura, postinfectious purpura, purpura fulminans, and anaphylactoid purpura. These syndromes have variable courses, with febrile purpura being the most benign of the syndromes and having an uncomplicated outcome. In contrast, malignant chickenpox with purpura is a grave clinical condition that has a mortality rate of greater than 70%. The etiology of these hemorrhagic chickenpox syndromes is not known.^[47]

See also

• List of cutaneous conditions
• Pox party

References

1. ^ Wood MJ (October 2000). "History of Varicella Zoster Virus". Herpes 7 (3): 60–65. PMID 11867004. http://www.ncbi.nlm.nih.gov/pubmed/11867004. 
2. ^ "Chickenpox". Medline Plus. 2009-09-13. http://www.nlm.nih.gov/medlineplus/ency/article/001592.htm. Retrieved 2011-06-12. 
3. ^ http://uhs.berkeley.edu/home/healthtopics/chickenpox.shtml
4. ^ Centers for Disease Control and Protection (2010-12-27). "Varicella Pink Book Chapter 20 p289 Communicability". http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/varicella.pdf. Retrieved 2010-12-27. 
5. ^ "General questions about the disease". Varicella Disease (Chickenpox). CDCP. 2001-12-02. http://www.cdc.gov/vaccines/vpd-vac/varicella/dis-faqs-gen.htm. Retrieved 2006-08-18. 
6. ^ Stroke.ahajournals.org
7. ^ Cohen JI, Moskal T, Shapiro M, Purcell RH (December 1996). "Varicella in Chimpanzees". Journal of Medical Virology 50 (4): 289–92. doi:10.1002/(SICI)1096-9071(199612)50:4<289::AID-JMV2>3.0.CO;2-4. PMID 8950684. 
8. ^ Myers MG, Kramer LW, Stanberry LR (December 1987). "Varicella in a gorilla". Journal of Medical Virology 23 (4): 317–22. doi:10.1002/jmv.1890230403. PMID 2826674. 
9. ^ McPherson & Pincus: Henry's Clinical Diagnosis and Management by Laboratory Methods, 21st ed., 2007, Chapter 54.
10. ^ ^{a b c} Royal College of Obstetricians and Gynaecologists (September 2007). "Chickenpox in Pregnancy" (PDF). http://www.rcog.org.uk/files/rcog-corp/uploaded-files/GT13ChickenpoxinPregnancy2007.pdf. Retrieved 2009-07-22. 
11. ^ Abendroth A, Arvin AM (2001). "Immune evasion as a pathogenic mechanism of varicella zoster virus". Semin Immunol 13 (1): 27–39. doi:10.1006/smim.2001.0293. PMID 11289797. 
12. ^ Wharton M (1996). "The epidemiology of varicella-zoster virus infections". Infect Dis Clin North Am 10 (3): 571–81. doi:10.1016/S0891-5520(05)70313-5. PMID 8856352. 
13. ^ "Epidemiology of Varicella Zoster Virus Infection, Epidemiology of VZV Infection, Epidemiology of Chicken Pox, Epidemiology of Shingles". http://virology-online.com/viruses/VZV3.htm. Retrieved 2008-04-22. 
14. ^ Brannon, Heather (2007-07-22). "Chicken Pox in Pregnancy". Dermatology. About.com. http://dermatology.about.com/cs/pregnancy/a/chickenpreg.htm. Retrieved 2009-06-20. 
15. ^ "Chickenpox in Pregnancy". March of Dimes. April 2007. http://www.marchofdimes.com/professionals/14332_1185.asp. 
16. ^ Boussault P, Boralevi F, Labbe L, Sarlangue J, Taïeb A, Leaute-Labreze C (2007). "Chronic varicella-zoster skin infection complicating the congenital varicella syndrome". Pediatr Dermatol 24 (4): 429–32. doi:10.1111/j.1525-1470.2007.00471.x. PMID 17845179. http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0736-8046&date=2007&volume=24&issue=4&spage=429. 
17. ^ Matsuo T, Koyama M, Matsuo N (July 1990). "Acute retinal necrosis as a novel complication of chickenpox in adults". Br J Ophthalmol 74 (7): 443–4. doi:10.1136/bjo.74.7.443. PMC 1042160. PMID 2378860. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1042160. 
18. ^ Sauerbrei, Andreas; Wutzler, Peter (December 2001). "Neonatal Varicella". Journal of Perinatology. 21 (8): 545–549.
19. ^ NHS.uk
20. ^ [1]
21. ^ [2]
22. ^ [3]
23. ^ Patrick R. Murray et al., Medical Microbiology, 5th edition (Elsevier), p.551.
24. ^ Chaves SS, Gargiullo P, Zhang JX, et al. (2007). "Loss of vaccine-induced immunity to varicella over time". N Engl J Med 356 (11): 1121–9. doi:10.1056/NEJMoa064040. PMID 17360990. 
25. ^ [4], CDC Child & Adolescent Immunization Schedules
26. ^ NHS.uk
27. ^ "Chickenpox (varicella)". http://www.netdoctor.co.uk/diseases/facts/chickenpox.htm. Retrieved 2010-11-06. 
28. ^ "Varicella Zoster Virus". http://www.varicellazoster.net/. Retrieved 2010-11-06. 
29. ^ Tebruegge M, Kuruvilla M, Margarson I (2006). "Does the use of calamine or antihistamine provide symptomatic relief from pruritus in children with varicella zoster infection?" (Abstract). Arch. Dis. Child. 91 (12): 1035–6. doi:10.1136/adc.2006.105114. PMC 2082986. PMID 17119083. http://adc.bmj.com/cgi/content/extract/91/12/1035. 
30. ^ Domino, Frank J. (2007). The 5-Minute Clinical Consult, 2007. Lippincott Williams & Wilkins. p. 248. ISBN 978-0-7817-6334-9.
31. ^ Brannon, Heather (May 21, 2008). Chicken Pox Treatments. About.com.
32. ^ Parmet, Sharon; Lynm, Cassio (February 18, 2004). Chickenpox. Journal of the American Medical Association. 291 (7): 906.
33. ^ ^{a b} "Antiviral medications for chickenpox". http://children.webmd.com/vaccines/antiviral-medications-for-chickenpox. Retrieved 2011-03-27. 
34. ^ "Chickenpox in Children Under 12". http://www.patient.co.uk/health/Chickenpox-in-Children-Under-12.htm. Retrieved 2010-11-06. 
35. ^ "Reye's Syndrome-Topic Overview". http://children.webmd.com/tc/reyes-syndrome-topic-overview. Retrieved 2011-03-27. 
36. ^ [5]
37. ^ "What is chickenpox?". http://www.patient.co.uk/health/Chickenpox-in-Adults-and-Teenagers.htm. Retrieved 2010-11-06. 
38. ^ "Chickenpox: Treatment & Medication". http://emedicine.medscape.com/article/1131785-treatment. Retrieved 2010-11-06. 
39. ^ Somekh E, Dalal I, Shohat T, Ginsberg GM, Romano O (2002). "The burden of uncomplicated cases of chickenpox in Israel". J. Infect. 45 (1): 54–7. doi:10.1053/jinf.2002.0977. PMID 12217733. 
40. ^ US Centers for Disease Control and Prevention. "Varicella Treatment Questions & Answers". CDC Guidelines. CDC. http://www.cdc.gov/vaccines/vpd-vac/varicella/dis-faqs-gen-treatment.htm. Retrieved 2007-08-23. 
41. ^ Jill M. Baren MD, Philip L. Henneman MD, Roger J. Lewis MD, PhD (August 1996). "Primary Varicella in Adults: Pneumonia, Pregnancy, and Hospital Admissions". Annals of Emergency Medicine 28 (2): 165–169. doi:10.1016/S0196-0644(96)70057-4. PMID 8759580. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WB0-4HG68T8-7&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1152674350&_rerunOrigin=scholar.google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=079d9dd0e57fad57f6095f23278630aa. 
42. ^ < ERJ.ersjournals.com
43. ^ "Definition of Chickenpox". MedicineNet.com. http://www.medterms.com/script/main/art.asp?articlekey=2702. Retrieved 2006-08-18. 
44. ^ "Is Necrotizing Fasciitis a complication of Chickenpox of Cutaneous Vasculitis?". atmedstu.com. http://www.atmedstu.com/exam%20plus/Is%20Necrotizing%20Fasciitis%20a%20complication%20of%20Chickenpox%20or%20of%20Cutaneous%20Vasculitis.php. Retrieved 2008-01-18. 
45. ^ Strangfeld A, Listing J; Herzer, P.; , et al; Liebhaber, A.; Rockwitz, K.; Richter, C.; Zink, A. (2009). "Risk of herpes zoster in patients with rheumatoid arthritis treated With anti–TNF-α agents". J Am Med Assoc 301 (7): 737–744. doi:10.1001/jama.2009.146. PMID 19224750. 
46. ^ Weller TH (1997). "Varicella-herpes zoster virus". In Evans AS, Kaslow RA. Viral Infections of Humans: Epidemiology and Control. Plenum Press. pp. 865–92. ISBN 978-0306448553. 
47. ^ ^{a b} Chicken Pox Complications

External links

• Chickenpox at the Open Directory Project
• Chicken pox care map Map of Medicine, Updated July 2010

v d e Diseases of the skin and appendages by morphology Growths Epidermal wart callus seborrheic keratosis acrochordon molluscum contagiosum actinic keratosis squamous cell carcinoma basal cell carcinoma merkel cell carcinoma nevus sebaceous trichoepithelioma Pigmented Freckles lentigo melasma nevus melanoma Dermal and subcutaneous epidermal inclusion cyst hemangioma dermatofibroma keloid lipoma neurofibroma xanthoma Kaposi's sarcoma infantile digital fibromatosis granular cell tumor leiomyoma lymphangioma circumscriptum myxoid cyst Rashes With epidermal involvement Eczematous contact dermatitis atopic dermatitis seborrheic dermatitis stasis dermatitis lichen simplex chronicus Darier's disease glucagonoma syndrome langerhans cell histiocytosis lichen sclerosus pemphigus foliaceus Wiskott-Aldrich syndrome Zinc deficiency Scaling psoriasis tinea (corporis cruris pedis manuum faciei) pityriasis rosea secondary syphillis mycosis fungoides systemic lupus erythematosus pityriasis rubra pilaris parapsoriasis ichthyosis Blistering herpes simplex herpes zoster varicella bullous impetigo acute contact dermatitis pemphigus vulgaris bullous pemphigoid dermatitis herpetiformis porphyria cutanea tarda epidermolysis bullosa simplex Papular scabies insect bite reactions lichen planus miliaria keratosis pilaris lichen spinulosus transient acantholytic dermatosis lichen nitidus pityriasis lichenoides et varioliformis acuta Pustular acne vulgaris acne rosacea folliculitis impetigo candidiasis gonococcemia dermatophyte coccidioidomycosis subcorneal pustular dermatosis Hypopigmented tinea versicolor vitiligo pityriasis alba postinflammatory hyperpigmentation tuberous sclerosis idiopathic guttate hypomelanosis leprosy hypopigmented mycosis fungoides Without epidermal involvement Red Blanchable Erythema Generalized drug eruptions viral exanthems toxic erythema systemic lupus erythematosus Localized cellulitis abscess boil erythema nodosum carcinoid syndrome fixed drug eruption Specialized urticaria erythema (multiforme migrans gyratum repens annulare centrifugum ab igne) Nonblanchable Purpura Macular thrombocytopenic purpura actinic purpura Papular disseminated intravascular coagulation vasculitis Indurated scleroderma/morphea granuloma annulare lichen sclerosis et atrophicus necrobiosis lipoidica Miscellaneous disorders Ulcers Hair telogen effluvium androgenic alopecia trichotillomania alopecia areata systemic lupus erythematosus tinea capitis loose anagen syndrome lichen planopilaris folliculitis decalvans acne keloidalis nuchae Nail onychomycosis psoriasis paronychia ingrown nail Mucous membrane aphthous stomatitis oral candidiasis lichen planus leukoplakia pemphigus vulgaris mucous membrane pemphigoid cicatricial pemphigoid herpesvirus coxsackievirus syphilis systemic histoplasmosis squamous cell carcinoma

v d e Infectious skin disease: Viral cutaneous conditions, including viral exanthema (B00–B09, 050–059) DNA virus Herpesviridae Alpha HSV (Herpes simplex, Herpetic whitlow, Herpes gladiatorum, Herpetic keratoconjunctivitis, Herpetic sycosis, Neonatal herpes simplex, Herpes genitalis, Herpes labialis, Eczema herpeticum, Herpetiform esophagitis) · Herpes B virus (B virus infection) VZV (Chickenpox, Herpes zoster, Herpes zoster oticus, Ophthalmic zoster, Disseminated herpes zoster, Zoster-associated pain, Inflammatory skin lesions following zoster infection, Modified varicella-like syndrome) Beta Human herpesvirus 6/Roseolovirus (Exanthema subitum, Roseola vaccinia) Cytomegalic inclusion disease Gamma KSHV (Kaposi's sarcoma) Poxviridae Ortho Variola (Smallpox, Eczema vaccinatum, Alastrim) · MoxV (Monkeypox) · CV (Cowpox) · VV (Vaccinia, Generalized vaccinia, Progressive vaccinia) Buffalopox Para Farmyard pox: Milker's nodule · Bovine papular stomatitis · Pseudocowpox · Orf Sealpox Other Yatapoxvirus: Tanapox · Yaba monkey tumor virus MCV (Molluscum contagiosum) Papillomaviridae HPV (Wart/Plantar wart, Heck's disease, Genital wart (giant), Laryngeal papillomatosis, Butcher's wart, Bowenoid papulosis, Epidermodysplasia verruciformis, Verruca plana, Pigmented wart, Verrucae palmares et plantares ) BPV (Equine sarcoid) Parvoviridae Parvovirus B19 (Erythema infectiosum, Reticulocytopenia, Papular purpuric gloves and socks syndrome) RNA virus Paramyxoviridae MeV (Measles) Togaviridae Rubella virus (Rubella, Congenital rubella syndrome) · Alphavirus infection · Chikungunya fever Picornaviridae CAV (Hand, foot and mouth disease, Herpangina) · FMDV (Foot-and-mouth disease) · Boston exanthem disease Ungrouped unknown/multiple: Asymmetric periflexural exanthem of childhood · Post-vaccination follicular eruption · Lipschütz ulcer · Eruptive pseudoangiomatosis · Viral-associated trichodysplasia · Gianotti–Crosti syndrome M: VIR virs(prot)/clss cutn/syst (hppv/hiva, infl/zost/zoon)/epon drugJ(dnaa, rnaa, rtva, vacc) M: INT, SF, LCT anat/phys/devp noco(i/b/d/q/u/r/p/m/k/v/f)/cong/tumr(n/e/d), sysi/epon proc, drug (D2/3/4/5/8/11)

v d e Varicella zoster Infections Chickenpox · Herpes zoster · Postherpetic neuralgia  · Ramsay Hunt syndrome type II Other Varicella zoster virus · Varicella vaccine · Zostavax · Pox party M: VIR virs(prot)/clss cutn/syst (hppv/hiva, infl/zost/zoon)/epon drugJ(dnaa, rnaa, rtva, vacc)

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