|Classification and external resources|
Lower leg of female child with varicella disease
|eMedicine||ped/2385 derm/74, emerg/367|
Chickenpox is a highly contagious disease caused by primary infection with varicella zoster virus (VZV). It usually starts with a vesicular skin rash mainly on the body and head rather than on the limbs. The rash develops into itchy, raw pockmarks, which mostly heal without scarring. On examination, the observer typically finds skin lesions at various stages of healing and also ulcers in the oral cavity and tonsil areas. The disease is most commonly observed in children.
Chickenpox is an airborne disease which spreads easily through coughing or sneezing by 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. They remain contagious until all lesions have crusted over (this takes approximately six days). Immunocompromised patients are contagious during the entire period as new lesions keep appearing. Crusted lesions are not contagious.
The origin of the term chicken pox, which is recorded as being used since 1684, is not reliably known. It has been said to be a derived from chickpeas, based on resemblance of the vesicles to chickpeas, or to come from the rash resembling chicken pecks. Other suggestions include the designation chicken for a child (i.e., literally 'child pox'), a corruption of itching-pox, or the idea that the disease may have originated in chickens. Samuel Johnson explained the designation as "from its being of no very great danger."
Signs and symptoms
The early (prodromal) symptoms in adolescents and adults are nausea, loss of appetite, aching muscles, and headache. This is followed by the characteristic rash or oral sores, malaise, and a low-grade fever that signal the presence of the disease. Oral manifestations of the disease (enanthem) not uncommonly may precede the external rash (exanthem). In children the illness is not usually preceded by prodromal symptoms, and the first sign is the rash or the spots in the oral cavity. The rash begins as small red dots on the face, scalp, torso, upper arms and legs; progressing over 10–12 hours to small bumps, blisters and pustules; followed by umbilication and the formation of scabs.
At the blister stage, intense itching is usually present. Blisters may also occur on the palms, soles, and genital area. Commonly, visible evidence of the disease develops in the oral cavity & tonsil areas in the form of small ulcers which can be painful or itchy or both; this enanthem (internal rash) can precede the exanthem (external rash) by 1 to 3 days or can be concurrent. These symptoms of chickenpox appear 10 to 21 days after exposure to a contagious person. Adults may have a more widespread rash and longer fever, and they are more likely to experience complications, such as varicella pneumonia.
Because watery nasal discharge containing live virus usually precedes both exanthem (external rash) and enanthem (oral ulcers) by 1 to 2 days, the infected person actually becomes contagious one to two days prior to recognition of the disease. Contagiousness persists until all vesicular lesions have become dry crusts (scabs), which usually entails four or five days, by which time nasal shedding of live virus also ceases.
Chickenpox is rarely fatal, although it is generally more severe in adult men than in women or children. Non-immune pregnant women and those with a suppressed immune system are at highest risk of serious complications. Arterial ischemic stroke (AIS) associated with chickenpox in the previous year accounts for nearly one third of childhood AIS. The most common late complication of chickenpox is shingles (herpes zoster), caused by reactivation of the varicella zoster virus decades after the initial, often childhood, chickenpox infection.
The diagnosis of varicella is primarily clinical, with typical early "prodromal" symptoms, and then the characteristic rash and oral-cavity sores. 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 Tzanck smear, or better by testing 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).
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.
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. Varicella zoster can affect the arteries in the neck and head, producing stroke, either during childhood, or after a latency period of many years.
Pregnancy and neonates
During pregnancy the dangers to the fetus associated with a primary VZV infection are greater in the first six months. In the third trimester, the mother is more likely to suffer from the adverse effects of the infection. For pregnant women, antibodies produced as a result of immunization or previous infection are transferred via the placenta to the fetus. 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.
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). 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, 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". 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.
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). The United States Advisory Committee on Immunization Practices (ACIP) suggests that any adult over the age of 60 years gets the herpes zoster vaccine as a part of their normal medical check ups.
Many adults who have had chickenpox as children are susceptible to shingles as adults, often with the accompanying condition postherpetic neuralgia, a painful condition that makes it difficult to sleep. Even after the shingles rash has gone away, there can be night pain in the area affected by the rash.
Shingles affects one in five adults infected with chickenpox as children, 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.
Shingles are most commonly found in adults over the age of 60 who were diagnosed with chickenpox when they were under the age of 1.
A shingles vaccine is available for adults over 50 who have had childhood chickenpox or who have previously had shingles.
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. The chickenpox virus is susceptible to disinfectants, notably chlorine bleach (i.e., sodium hypochlorite). Also, like all enveloped viruses, it is sensitive to desiccation, heat and detergents.
A varicella vaccine was first developed by Michiaki Takahashi in 1974 derived from the Oka strain. It has been available in the US 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, which is currently part of the routine immunization schedule in the US. 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 vaccinated person is likely to have a milder case of chickenpox if infected.
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 suppresses the virus in 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. 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.
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. It is important to maintain good hygiene and daily cleaning of skin with warm water to avoid secondary bacterial infection. Scratching may also increase the risk of secondary infection.
Acetaminophen (paracetamol) but not aspirin may be used to reduce fever. Aspirin use by someone with chickenpox may cause the serious, sometimes fatal disease of the liver and brain, Reye syndrome. People at risk of developing severe complications who have had significant exposure to the virus may be given intra-muscular varicella zoster immune globulin (VZIG), a preparation containing high titres of antibodies to varicella zoster virus, to ward off the disease.
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 unless they are suffering from another medical condition which would put them at risk of developing complications.
Treatment of chickenpox in children is aimed at symptoms while 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 scratch their blisters more deeply than adults.
Some parents believe that it is better for children to contract chickenpox than to get the vaccine, and they deliberately expose their children to the virus, sometimes by taking them to "chickenpox parties." Some doctors counter that children are safer getting the vaccine, which is a weakened form of the virus, than getting the disease, which can be fatal.
Infection in otherwise healthy adults tends to be more severe. 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. 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 itches and may be used in cases where the itches 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.
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.
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, it is recommended to keep new infants from birth till 6 months of age away from an infected person for 10 to 21 days as their immune systems are not developed enough to handle the stress it can bring on. 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.
In adults, the disease is more severe, though the incidence is much less common. Infection in adults is associated with greater morbidity and mortality due to pneumonia (either direct viral pneumonia or secondary bacterial pneumonia), hepatitis, and encephalitis. 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. Inflammation of the brain, or encephalitis, can occur in immunocompromised individuals, although the risk is higher with herpes zoster. Necrotizing fasciitis is also a rare complication.
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 of immunosuppressive therapies. Varicella is a particular problem in hospitals, when there are patients with immune systems weakened by drugs (e.g., high-dose steroids) or HIV.
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.
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.
Primary varicella occurs in all countries worldwide. Varicella has a prevalence that is stable from generation to generation. As of 2010 it caused about 6,800 deaths, down from 11,200 in 1990.
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, and 10% of young adults remain susceptible.
In the United States, the Centers for Disease Control and Prevention (CDC) does not require state health departments to report infections of chicken pox, and only 31 states currently volunteer this information. However, in a 2013 study conducted by the social media disease surveillance tool called Sickweather, anecdotal reports of chickenpox infections on Facebook and Twitter were used to measure and rank states with the most infections per capita, with Maryland, Tennessee and Illinois in the top 3.
- Wood MJ (October 2000). "History of Varicella Zoster Virus". Herpes 7 (3): 60–65. PMID 11867004.
- MedlinePlus Encyclopedia Chickenpox
- UHS Tang Center
- Centers for Disease Control and Prevention (2012). "Ch. 21: Varicella". In Atkinson W, Wolfe S, Hamborsky J. Epidemiology and Prevention of Vaccine-Preventable Diseases (12th ed.). Washington DC: Public Health Foundation. pp. 301–323. "The virus has not been isolated from crusted lesions."
- 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.
- 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.
- Chicken-pox is recorded in Oxford English Dictionary 2nd ed. since 1684; the OED records several suggested etymologies
- Belshe, Robert B. (1984). Textbook of human virology (2nd ed.). Littleton MA: PSG. p. 829. ISBN 0-88416-458-6.
- Teri Shors (2011). "Herpesviruses: Varicella Zoster Virus (VZV)". Understanding Viruses (2nd ed.). Jones & Bartlett. p. 459. ISBN 978-0-7637-8553-6.
- Pattison, John; Zuckerman, Arie J.; Banatvala, J.E. (1994). Principles and practice of clinical virology (3rd ed.). Wiley. p. 37. ISBN 0-471-93106-3.
- Johnson, Samuel (1839). Dictionary of the English language. London: Williamson. p. 195.
- Anthony J Papadopoulos. "Chickenpox Clinical Presentation". In Dirk M Elston. Medscape Reference. Retrieved 4 August 2012.
- "Symptoms of Chickenpox". Chickenpox. NHS Choices. Retrieved 14 March 2013.
- Askalan R, Laughlin S, Mayank S, Chan A, MacGregor D, Andrew M, Curtis R, Meaney B, deVeber G (June 2001). "Chickenpox and stroke in childhood: a study of frequency and causation". Stroke 32 (6): 1257–62. doi:10.1161/01.STR.32.6.1257. PMID 11387484.
- Pincus, Matthew R.; McPherson, Richard A.; Henry, John Bernard (2007). "Ch. 54". Henry's clinical diagnosis and management by laboratory methods (21st ed.). Saunders Elsevier. ISBN 1-4160-0287-1.
- Royal College of Obstetricians and Gynaecologists (September 2007). "Chickenpox in Pregnancy" (PDF). Retrieved 2009-07-22.
- Kanbayashi Y, Onishi K, Fukazawa K, Okamoto K, Ueno H, Takagi T, Hosokawa T (2012). "Predictive Factors for Postherpetic Neuralgia Using Ordered Logistic Regression Analysis". The Clinical Journal of Pain 28 (8): 712–714. doi:10.1097/AJP.0b013e318243ee01. PMID 22209800.
- Pino Rivero V, González Palomino A, Pantoja Hernández CG, Mora Santos ME, Trinidad Ramos G, Blasco Huelva A (2006). "Ramsay-Hunt syndrome associated to unilateral recurrential paralysis". Anales otorrinolaringologicos ibero-americanos 33 (5): 489–494. PMID 17091862.
- "The varicella zoster virus vasculopathies: clinical, CSF, imaging, and virologic features.". Neurology. March 2008.
- Heuchan AM, Isaacs D (Mar 19, 2001). "The management of varicella-zoster virus exposure and infection in pregnancy and the newborn period. Australasian Subgroup in Paediatric Infectious Diseases of the Australasian Society for Infectious Diseases.". The Medical journal of Australia 174 (6): 288–92. PMID 11297117.
- Brannon, Heather (2007-07-22). "Chickenpox in Pregnancy". Dermatology. About.com. Retrieved 2009-06-20.
- "Chickenpox in Pregnancy". March of Dimes. April 2014.
- 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.
- 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.
- Mazzella M, Arioni C, Bellini C, Allegri AE, Savioli C, Serra G (2003). "Severe hydrocephalus associated with congenital varicella syndrome". CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne 168 (5): 561–563. PMC 149248. PMID 12615748.
- Sauerbrei A, Wutzler P (December 2001). "Neonatal varicella". J Perinatol 21 (8): 545–9. doi:10.1038/sj.jp.7210599. PMID 11774017.
- "Chickenpox". NHS Choices. UK Department of Health. 19 April 2012.
- "Shingles & Chickenpox: What's the Link?". WebMD.
- "An Overview of Shingles". WebMD.
- "Shingles". PubMed Health.
- "Shingles Vaccine". WebMD.
- Murray, Patrick R.; Rosenthal, Ken S.; Pfaller, Michael A. (2005). Medical Microbiology (5th ed.). Elsevier Mosby. p. 551. ISBN 0-323-03303-2., edition (Elsevier), p..
- Chaves SS, Gargiullo P, Zhang JX, Civen R, Guris D, Mascola L, Seward JF (2007). "Loss of vaccine-induced immunity to varicella over time". N Engl J Med 356 (11): 1121–9. doi:10.1056/NEJMoa064040. PMID 17360990.
- "Child, Adolescent & "Catch-up" Immunization Schedules". Immunization Schedules. Centers for Disease Control and Prevention.
- "Chickenpox (varicella) vaccination". NHS Choices. UK Department of Health. 19 April 2012.
- "Chickenpox (varicella)". Retrieved 2010-11-06.
- "Varicella Zoster Virus". Retrieved 2010-11-06.
- 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.
- Domino, Frank J. (2007). The 5-Minute Clinical Consult. Lippincott Williams & Wilkins. p. 248. ISBN 978-0-7817-6334-9.
- Brannon, Heather (May 21, 2008). Chicken Pox Treatments. About.com.
- Parmet S, Lynm C, Glass RM (February 2004). "JAMA patient page. Chickenpox". JAMA 291 (7): 906. doi:10.1001/jama.291.7.906. PMID 14970070.
- Naus M et al. (15 October 2006). "Varizig™ as the Varicella Zoster Immune Globulin for the Prevention of Varicella In At-Risk Patients". Canada Communicable Disease Report 32 (ACS-8).
- Huff JC (Jan 1988). "Antiviral treatment in chickenpox and herpes zoster.". Journal of the American Academy of Dermatology 18 (1 Pt 2): 204–6. doi:10.1016/S0190-9622(88)70029-8. PMID 3339143.
- Gnann Jr, John W. (2007). "Chapter 65Antiviral therapy of varicella-zoster virus infections". In Arvin, Ann; et.al. Human herpesviruses : biology, therapy, and immunoprophylaxis. Cambridge: Cambridge University Press. ISBN 978-0-521-82714-0. Retrieved 20 January 2014.
- Kay AB (2001). "Allergy and allergic diseases. First of two parts". The New England Journal of Medicine 344 (1): 30–7. doi:10.1056/NEJM200101043440106. PMID 11136958.
- Kay AB (2001). "Allergy and allergic diseases. Second of two parts". The New England Journal of Medicine 344 (2): 109–13. doi:10.1056/NEJM200101113440206. PMID 11150362.
- "Chickenpox in Children Under 12". Retrieved 2010-11-06.
- "Reye's Syndrome-Topic Overview". Retrieved 2011-03-27.
- "Chicken Pox parties do more harm than good, says doctor". KSLA News 12 Shreveport, Louisiana News Weather & Sports.
- Tunbridge AJ, Breuer J, Jeffery KJ (August 2008). "Chickenpox in adults - clinical management". The Journal of Infection 57 (2): 95–102. doi:10.1016/j.jinf.2008.03.004. PMID 18555533.
- "What is chickenpox?". Retrieved 2010-11-06.
- Chickenpox~treatment at eMedicine
- 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.
- US Centers for Disease Control and Prevention. "Varicella Treatment Questions & Answers". CDC Guidelines. CDC. Retrieved 2007-08-23.
- Baren JM, Henneman PL, Lewis RJ (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.
- Mohsen AH, McKendrick M (May 2003). "Varicella pneumonia in adults". Eur. Respir. J. 21 (5): 886–91. doi:10.1183/09031936.03.00103202. PMID 12765439.
- Anderson, D.R.; Schwartz, J.; Hunter, N.J.; Cottrill, C.; Bissaccia, E.; Klainer, A.S. (1994). "Varicella Hepatitis: A Fatal Case in a Previously Healthy, Immunocompetent Adult". Archives of Internal Medicine (JAMA) 154 (18): 2101–2106. doi:10.1001/archinte.1994.00420180111013.
- Abro AH, Ustadi AM, Das K, Abdou AM, Hussaini HS, Chandra FS (December 2009). "Chickenpox: presentation and complications in adults". Journal of Pakistan Medical Association 59 (12): 828–831. PMID 20201174. Retrieved 17 April 2013.
- "Definition of Chickenpox". MedicineNet.com. Retrieved 2006-08-18.
- "Is Necrotizing Fasciitis a complication of Chickenpox of Cutaneous Vasculitis?". atmedstu.com. Retrieved 2008-01-18.
- Strangfeld A, Listing J, Herzer P, Liebhaber A, Rockwitz K, Richter C, Zink A (February 2009). "Risk of herpes zoster in patients with rheumatoid arthritis treated with anti-TNF-alpha agents". JAMA 301 (7): 737–44. doi:10.1001/jama.2009.146. PMID 19224750.
- 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 978-0-306-44855-3.
- Chicken Pox Complications
- Abendroth A, Arvin AM (February 2001). "Immune evasion as a pathogenic mechanism of varicella zoster virus". Seminars in immunology 13 (1): 27–39. doi:10.1006/smim.2001.0293. PMID 11289797.
- Lozano R, Naghavi M, Foreman K, Lim S, Shibuya K, Aboyans V, Abraham J, Adair T, Aggarwal R, Ahn SY, et al. (Dec 15, 2012). "Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010". Lancet 380 (9859): 2095–128. doi:10.1016/S0140-6736(12)61728-0. PMID 23245604.
- 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.
- "Epidemiology of Varicella Zoster Virus Infection, Epidemiology of VZV Infection, Epidemiology of Chicken Pox, Epidemiology of Shingles". Retrieved 2008-04-22.
- "Georgia ranks 10th for social media admissions of chickenpox". Retrieved 2013-06-13.
- "Chickenpox in the USA". Retrieved 2013-06-12.
|Wikimedia Commons has media related to Chickenpox.|
- Chickenpox at DMOZ
- "Chicken pox care map". Map of Medicine. London, UK: Map of Medicine Limited.(registration required)
- "Prevention of Varicella: Recommendations of the Advisory Committee on Immunization Practices (ACIP)". Centers for Disease Control and Prevention (CDC). July 12, 1996. Retrieved 18 May 2013.
- "Management of Varicella Zoster Virus (VZV) Infections". Federal Bureau of Prisons: Clinical Practice Guideline. December 2011. Retrieved 18 May 2013.
- John W. Gnann Jr. (2007). Chapter 65 Antiviral therapy of varicella-zoster virus infections. PMID 21348091.
- Sarah McSweeney-Ryan; Megan Sandel. "The Health Care of Homeless Persons - Part I - Varicella (Chickenpox". Boston Health Care for the Homeless Program. Retrieved 18 May 2013.