Ver el código de «Varicella»

==Background==
*Caused by [[varicella zoster virus]] causing varicella (chicken pox) and later zoster ([[Shingles]]) 
*Contagious until last lesion crusts over
**Fluid from open vesicles contains live virus <ref name="Bode">Sara Bode; Contagious Exanthematous Diseases. ''Quick References 2022''; 10.1542/aap.ppcqr.396150</ref>
*Incubation period is 10-21 days with symptoms starting around day 14 <ref name="Bode"/>

{{Herpes viruses}}

==Clinical Features==
[[File:Vicki Pandit - Howrah 2014-04-06 9845.jpg|thumb|Chickenpox rash on face.]]
[[File:Varicela Rash.jpg|thumbnail|Male with varicella rash: lesions in various stages of development]]
[[File:Chickenpox blister.jpg|thumbnail|Classic blister during early stage of lesion development]]
*[[pruritus|Pruritic]] generalized vesicular exanthem with mild systemic manifestations
*Usually affects children <10y

===[[Rash]]===
*Starts on trunk or scalp as pruritic, red macules, spreads to extremities
*Within 24hr rash becomes vesicular (on erythematous base)
**Often referred to as "dew drop on a rose petal" <ref name="Bode"/>
*Palms/soles spared
*Lesions in various stages of development
*The number of lesions can vary; usually 300 or less but can be more than 2,000 <ref name="Bode"/>

===Complications===
*Can include [[encephalitis]], [[otitis media]], [[pneumonia]], [[hepatitis]], [[strep]]/[[staph]] [[cellulitis|superinfection]] of ruptured vesicles
*Perinatal infection in neonates may develop serious illness

==Differential Diagnosis==
{{Peds Rash DDX}}
{{Bullous rashes DDX}}
{{VZV types}}

==Evaluation==
*Typically made on clinical features

==Management==
===Supportive Care===
*[[Tylenol]], [[antihistamine]], oatmeal baths
*Avoid aspirin in young children due to the risk of [[Reye syndrome]]

===Antivirals===
*Routine use of antiretrovirals for uncomplicated cases in immunocompetent children is not recommended <ref>Arvin AM: Antiviral therapy for varicella and herpes zoster. Semin Pediatr Infect Dis 2002; 13:12.</ref>
*However, evidence shows decreased days of fever and number of lesions<ref>Klassen TP, et al. Acyclovir for treating varicella in otherwise healthy children and adolescents. Cochrane Database Syst Rev. 2005; (4):CD002980.</ref>
AAP recommends antiviral treatment (within 24hrs) for patients at risk of increased illness severity:
*Any patient older than 12 years of age
*Patients with chronic cutaneous or pulmonary disorders
*Patients receiving long-term salicylate therapy
*Patients receiving short, intermittent, or aerosolized courses of corticosteroids

Other cases to consider [[acyclovir]]
*Also consider in <ref>Drugs for non-HIV viral infections. Treat Guidel Med Lett. 2007; 5(59):59-70.</ref>:
*Pregnancy<ref name="cdc">CDC Chicken pox acyclovir treatment [http://www.cdc.gov/chickenpox/hcp/persons-risk.html#acyclovir]</ref>
====Immunocompetent Adult====
*[[Acyclovir]] 800mg PO q6hrs daily x 5 days '''OR'''
*[[Valacyclovir]] 1000mg PO q8hrs daily x 14 days '''OR'''
*[[Famiciclovir]] 500mg PO q8hrs x 14 days
====Immunocompromised Adult====
*[[Acyclovir]] 10mg/kg IV q8hrs x 7 days
====At risk children <12yo child based on AAP criteria====
*[[Acyclovir]] 20mg/kg PO q6hrs daily x 5 days
*[[Acyclovir]] 10mg/kg IV q8hrs daily x 7 days

====VZIG====
*Initiate VZIG alongside acyclovir for inpatient treatment of child or adult
*For immunocompromised child with exposure, give as post-exposure prophylaxis if<ref>CDC. MMWR - updated recommendations for use of VariZIG - United States, 2013. July 19, 2013 / 62(28);574-576.</ref>:
**Within 10 days window of exposure
**VZIG given IM as 125 IU/10 kg of body weight
***Up to max of 625 IU
***Minimum dose 62.5 IU for patients weighing ≤ 2.0 kg
***Minimum dose 125 IU for weight 2.1 - 10.0 kg
*VZIG may prolong incubation period ≥1 week
**Must have patient closely follow up for signs and symptoms for 28 days after exposure
**If signs or symptoms of varicella occur, antiviral therapy must be started immediately

==Disposition==
*Most often discharge
*Secondary bacterial infection most common cause of hospitalization in kids
*Pneumonia most common cause of hospitalization in adults<ref>Reynolds MA, Watson BM, Plott-Adams KK, et al. Epidemiology of varicella hospitalizations in the United States, 1995-2005. J Infect Dis. 2008;197 Suppl 2:S120-S126. doi:10.1086/522146</ref>

==Vaccine==
*Introduced in 2006. Prior to introduction, incidence prior to adolescence approached 90% in US
*Vaccine is 85% effective against all disease, 90% effective against severe disease (greater than 1000 lesions)
*Typically given at age 5 in USA
*Post-exposure prophylaxis:
**Ideally given within 3-5 days of exposure in immunocompetent patients
**If immunocompromised patient is being given VZIG, varicella vaccine should be administered ≥5 months after VariZIG administration<ref>CDC. Prevention of varicella: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 2007;56(No. RR-4).</ref>

==See Also==
*[[Pediatric Rashes]]
*[[Varicella zoster virus]]

==References==
<references/>

[[Category:Dermatology]]
[[Category:ID]]
[[Category:Pediatrics]]