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'''Chickenpox''' or '''chicken pox''' is a highly [[Infectious disease|contagious]] illness caused by primary [[infection]] with [[varicella zoster virus]] (VZV).<ref> {{cite journal |author=Wood MJ |title=History of Varicella Zoster Virus |journal=Herpes |volume=7 |issue=3 |pages=60–65 |year=2000 |month=October |pmid=11867004 |doi= |url=http://www.ncbi.nlm.nih.gov/pubmed/11867004}}</ref> It usually starts with [[Vesicle (dermatology)|vesicular]] skin [[rash]] mainly on the body and head rather than at the periphery and become itchy, raw [[pockmarks]], which mostly heal without scarring.
'''Chickenpox''' or '''chicken pox''' is a highly [[Infectious disease|contagious]] illness caused by primary [[infection]] with [[varicella zoster virus]] (VZV).<ref> {{cite journal |author=Wood MJ |title=History of Varicella Zoster Virus |journal=Herpes |volume=7 |issue=3 |pages=60–65 |year=2000 |month=October |pmid=11867004 |doi= |url=http://www.ncbi.nlm.nih.gov/pubmed/11867004}}</ref> It usually starts with [[Vesicle (dermatology)|vesicular]] skin [[rash]] mainly on the body and head rather than at the periphery and become itchy, raw [[pockmarks]], which mostly heal without scarring.
HEY FIFI!!! LOL

Chicken pox is spread easily through coughs or sneezes of ill individuals or through direct contact with secretions from the rash. Following primary infection there is usually lifelong protective immunity from further episodes of chickenpox.
Chicken pox is spread easily through coughs or sneezes of ill individuals or through direct contact with secretions from the rash. Following primary infection there is usually lifelong protective immunity from further episodes of chickenpox.


Revision as of 02:27, 8 June 2010

"Varicella" redirects here. For the interactive fiction computer game, see Varicella (computer game).
For other uses, see Chickenpox (disambiguation).
Chickenpox
SpecialtyInfectious diseases, pediatrics Edit this on Wikidata

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 become itchy, raw pockmarks, which mostly heal without scarring. HEY FIFI!!! LOL Chicken pox is spread easily through coughs or sneezes of ill individuals or through direct contact with secretions from the rash. Following primary infection there is usually lifelong protective immunity from further episodes of chickenpox.

Chickenpox is rarely fatal, although it is generally more severe in adult males than in adult females or children. Pregnant women and those with a suppressed immune system are at highest risk of serious complications. Chicken pox is now believed to be the cause of one third of stroke cases in children.[2] The most common late complication of chicken pox 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[3] and gorillas.[4]

Signs and symptoms

Chickenpox is a highly infectious disease that spreads from person to person by direct contact or by air from an infected person's coughing or sneezing. Touching the fluid blister can also spread the disease. A person with chickenpox is infectious from one to five days before the rash appears.[5] The contagious period continues until all blisters have formed scabs, which may take 5 to 10 days.[6] After the spots have scabbed over, the sufferer is still highly contagious, from 10 to 21 days, meaning they can still spread the virus through close contact, breathing, and even sleeping in someone's bed. It takes from 10 to 21 days after contact with an infected person for someone to develop chickenpox. Chickenpox (varicella) is often heralded by a prodrome of anorexia, myalgia, nausea, fever, headache, sore throat, pain in both ears, complaints of pressure in head or swollen face, and malaise in adolescents and adults, while 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), and anorexia. Rarely cough, rhinitis, abdominal pain, and gastrointestinal distress has been reported in patients with varicella. Typically, the disease is more severe in adults.[7]

  • A single blister, typical during the early stages of the rash
    A single blister, typical during the early stages of the rash
  • The back of a 30-year-old male, taken on day 5 of the rash
    The back of a 30-year-old male, taken on day 5 of the rash

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).[8]

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 foetal varicella syndrome.[9]

Epidemiology

Primary varicella is an endemic disease. Cases of varicella are seen throughout the year but more commonly in winter and early spring. Varicella 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. Most people become infected before adulthood but 10% of young adults remain susceptible.

Historically, varicella has been a disease predominantly affecting preschool and school-aged children. In adults the pock marks are darker and the scars more prominent than in children.[10]

Pathophysiology

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), 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.[11] 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.[12]

Varicella infection in pregnant women can 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).[13] Effects on the fetus can range in severity from underdeveloped toes and fingers to severe anal and bladder malformation. Possible problems include:

Infection late in gestation or immediately following birth is referred to as "neonatal varicella".[15] 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.[9]

Prevention

Hygiene measures

The spread of chicken pox 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.[16] Therefore, avoidance of close proximity or physical contact with affected individuals during that period will prevent contagion. The chicken pox 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.

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 is not lifelong and further vaccination is necessary five years after the initial immunization.[17]

Treatment

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.[18] It is important to maintain good hygiene and daily cleaning of skin with warm water to avoid secondary bacterial infection.[19] Scratching may also increase the risk of secondary infection.[20] Addition of a small quantity of vinegar to the water is sometimes advocated. Painkillers could be taken to prevent feeling itchy [21]

To relieve the symptoms of chicken pox, people commonly use anti-itching creams and lotions. These lotions are not to be used on the face or close to the eyes. An oatmeal bath also might help ease discomfort.[22]

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 those on immunosuppressive medication).[23]

Adults

Infection in otherwise healthy adults tends to be more severe and active; treatment with antiviral drugs (e.g. acyclovir) is generally advised, as long as it is started within 24–48 hours from rash onset.[24]

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.[25] Paracetamol (acetaminophen) is widely used to reduce fever. Aspirin, or products containing aspirin, must not be given to children with chickenpox as this risks causing Reye's Syndrome.[26]

In adults, the disease is more severe,[27] though the incidence is much less common. Infection in adults is associated with greater morbidity and mortality due to pneumonia,[28] 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.[9] Inflammation of the brain, or encephalitis, can occur in immunocompromised individuals, although the risk is higher with herpes zoster.[29] Necrotizing fasciitis is also a rare complication.[30]

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.[31]

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.[31]

History

Early rash of smallpox vs chickenpox: rash mostly on the torso is characteristic of chickenpox

Chickenpox was first identified by Persian scientist Muhammad ibn Zakariya ar-Razi (865–925), known to the West as "Rhazes", who clearly distinguished it from smallpox and measles.[32] Giovanni Filippo (1510–1580) of Palermo later provided a more detailed description of varicella (chickenpox).

See also

References

  1. ^ Wood MJ (2000). "History of Varicella Zoster Virus". Herpes. 7 (3): 60–65. PMID 11867004. {{cite journal}}: Unknown parameter |month= ignored (help)
  2. ^ http://stroke.ahajournals.org/cgi/content/abstract/32/6/1257
  3. ^ Cohen JI, Moskal T, Shapiro M, Purcell RH (19). "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. {{cite journal}}: |access-date= requires |url= (help); Check date values in: |year= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link) CS1 maint: year (link)
  4. ^ Myers MG, Kramer LW, Stanberry LR (1987). "Varicella in a gorilla". Journal of Medical Virology. 23 (4): 317–22. doi:10.1002/jmv.1890230403. PMID 2826674. {{cite journal}}: |access-date= requires |url= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  5. ^ "Onset of rashes in infectious disease". lifehugger. 2009-10-14. Retrieved 2009-10-14.
  6. ^ New Zealand Dermatological Society (2006-01-14). "Chickenpox (varicella)". Retrieved 2006-08-18.
  7. ^ "General questions about the disease". Varicella Disease (Chickenpox). CDCP. 2001-12-02. Retrieved 2006-08-18.
  8. ^ McPherson & Pincus: Henry's Clinical Diagnosis and Management by Laboratory Methods, 21st ed., 2007, Chapter 54.
  9. ^ a b c Royal College of Obstetricians and Gynaecologists (2007). "Chickenpox in Pregnancy" (PDF). Retrieved 2009-07-22. {{cite web}}: Unknown parameter |month= ignored (help)
  10. ^ "Epidemiology of Varicella Zoster Virus Infection, Epidemiology of VZV Infection, Epidemiology of Chicken Pox, Epidemiology of Shingles". Retrieved 2008-04-22.
  11. ^ Brannon, Heather (2007-07-22). "Chicken Pox in Pregnancy". Dermatology. About.com. Retrieved 2009-06-20.
  12. ^ "Chickenpox in Pregnancy". March of Dimes. 2007. {{cite web}}: Unknown parameter |month= ignored (help)
  13. ^ 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.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  14. ^ Matsuo T, Koyama M, Matsuo N (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. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  15. ^ Sauerbrei, Andreas; Wutzler, Peter (December 2001). "Neonatal Varicella". Journal of Perinatology. 21 (8): 545–549.
  16. ^ Patrick R. Murray et al., Medical Microbiology, 5th edition (Elsevier), p.551.
  17. ^ 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. {{cite journal}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: authors list (link)
  18. ^ 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.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  19. ^ Domino, Frank J. (2007). The 5-Minute Clinical Consult, 2007. Lippincott Williams & Wilkins. p. 248. ISBN 978-0781763349.
  20. ^ Brannon, Heather (May 21, 2008). Chicken Pox Treatments. About.com.
  21. ^ Gleeson, Rachael. "Chicken Pox - A Guide To Management - From Incubation To Recuperation". NaturalParenting. Retrieved 2009-06-20.
  22. ^ Parmet, Sharon; Lynm, Cassio (February 18, 2004). Chickenpox. Journal of the American Medical Association. 291 (7): 906.
  23. ^ "BestBets: Should acyclovir be prescribed for immunocompetent children presenting with chickenpox?".
  24. ^ http://www.patient.co.uk/health/Chickenpox-in-Adults-and-Teenagers.htm
  25. ^ 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.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  26. ^ US Centers for Disease Control and Prevention. "Varicella Treatment Questions & Answers". CDC Guidelines. CDC. Retrieved 2007-08-23.
  27. ^ Jill M Baren MD, Philip L Henneman MD, Roger J Lewis MD, PhD (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. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  28. ^ http://www.erj.ersjournals.com/cgi/content/abstract/21/5/886
  29. ^ "Definition of Chickenpox". MedicineNet.com. Retrieved 2006-08-18.
  30. ^ "Is Necrotizing Fasciitis a complication of Chickenpox of Cutaneous Vasculitis?". atmedstu.com. Retrieved 2008-01-18.
  31. ^ a b Chicken Pox Complications
  32. ^ Otri AM, Singh AD, Dua HS (2008). "Abu Bakr Razi". The British Journal of Ophthalmology. 92 (10): 1324. PMID 18815419. Retrieved 2009-06-20. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)

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