Approach Considerations
Primary varicella infection in the healthy child is a rather benign disease that requires symptomatic therapy only. Oral acyclovir should be considered for healthy persons at increased risk of severe varicella infections.
Adults and immunocompromised persons with chickenpox have a more complicated course than that occurring in children, and therefore, the condition necessitates a more aggressive pharmacotherapeutic approach. Intravenous acyclovir therapy is recommended for patients who are immunosuppressed or immunocompromised.
Varicella-zoster immune globulin (VariZIG) is indicated for use in highly susceptible, VZV-exposed immunocompromised or immunosuppressed populations. A live attenuated varicella vaccine (Oka strain) was approved by the FDA in 1995 for prophylactic use in healthy children and adults. [24, 25, 26, 27, 28]
While the current standard of care is with the antiviral agents discussed below, Lysimachia mauritiana extract appears promising as a potential agent. [29]
Also see the Guidelines section.
Treatment in Healthy Children
The symptoms of chickenpox in the pediatric population can be treated topically and with oral agents. Pruritus can be treated with calamine lotion or pramoxine gel; powdered oatmeal baths; or oral antihistamines.
The nucleoside analogue acyclovir (20 mg/kg PO qid for 5 d), though shown to decrease the symptoms and duration of primary varicella infection when administered within 24 hours of onset of symptoms, is not commonly prescribed for otherwise healthy children. [30]
Given the high risk of varicella-related complications, children should be treated if any of the following conditions are a medical concern:
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Defects in cell-mediated immunity
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Chronic atopic dermatitis
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Chronic asthma
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Iatrogenic immunosuppression
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Long-term systemic steroid use
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Splenic dysfunction
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Nephrotic syndrome
Go to Pediatric Chickenpox for more complete information on this topic.
Treatment in Immunocompetent Adults
Oral acyclovir should be considered for healthy persons at increased risk of severe varicella infections, most notably patients older than 12 years. Oral acyclovir therapy in this population (800 mg 5 times/d for 7 d), begun within 24 hours of onset of symptoms, has been shown to decrease the duration of lesions and pyrexia, while reducing other symptoms and disease duration.
Valacyclovir, the L-valyl ester of acyclovir, is a prodrug that has higher oral bioavailability than acyclovir. Valacyclovir is used in the treatment of herpes zoster, but no large-based clinical trials yet have demonstrated its efficacy in primary varicella infection of healthy, immunocompetent individuals.
Famciclovir is a prodrug of penciclovir, which is a nucleoside analogue similar to acyclovir. Like valacyclovir, famciclovir has demonstrated efficacy in the treatment of herpes zoster, but it has not been extensively studied for use in primary varicella infection of healthy populations.
A few case reports also have found sorivudine, a nucleoside analogue that is a potent in vivo inhibitor of varicella-zoster virus (VZV) replication, to be effective in the treatment of primary varicella in healthy adults. Larger scale clinical trials are needed to demonstrate the efficacy of this medication.
Treatment in the Immunocompromised or Immunosuppressed
Intravenous acyclovir therapy is recommended for patients who are immunosuppressed or immunocompromised, because of the life-threatening complications of primary varicella infection to which they are particularly susceptible. Severe disseminated disease, with the development of varicella pneumonia, encephalitis, hepatitis, and hemorrhagic complications, is much more common in this population than in other populations. [31]
Secondary complications (eg, bacterial pneumonia, meningitis) caused by bacterial superinfection of cutaneous lesions with subsequent septicemia, are also more common and dangerous among those who are immunocompromised.
Case reports have described vidarabine, a purine nucleoside analogue, and interferon-alpha to be effective in the treatment of primary varicella infection of immunocompromised hosts. Acyclovir-resistant strains of VZV have been reported in patients with AIDS.
Foscarnet, an inorganic pyrophosphate analogue that acts as a selective inhibitor of viral deoxyribonucleic acid polymerases and reverse transcriptases, is a potentially efficacious drug in patients with acyclovir-resistant VZV strains. Optimal dosage, duration of therapy, and efficacy in primary varicella infection need further investigation. Treatment of primary varicella in these populations is difficult and necessitates an integrated team approach. [32]
Continuing research into new antiviral agents and ongoing clinical trials are constantly adding new information relative to the pharmacotherapeutic options in the fight against VZV infections.
Passive Immunization
Varicella-zoster immune globulin (VariZIG), a human immunoglobulin preparation, is indicated for use in highly susceptible, VZV-exposed immunocompromised or immunosuppressed populations.
High risk groups include:
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Immunocompromised children and adults
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Newborns of mothers with varicella shortly before or after delivery
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Premature infants
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Infants less than one year of age
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Adults without evidence of immunity
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Pregnant women
VZIG given within 10 days (ideally within 96 hours) of exposure can modify the course of disease but does not prevent it. Maximal effectiveness is seen with administration as soon as possible after exposure. [33]
Varicella-Zoster Virus Vaccination
A live attenuated varicella vaccine (Oka strain) was approved by the US Food and Drug Administration in 1995 for prophylactic use in healthy children and adults. Vaccination recommendations consist of 1 dose for healthy children aged 12-18 months and 2 doses, in a 4- to 8-week interval, in susceptible persons older than 13 years. Studies in Japan point to high seroconversion rates and long-term immunity in children after vaccination. [24, 25, 26, 27, 28, 34] The need for revaccination, or a booster immunization, will be addressed after more long-term studies have been completed.
The effectiveness of the vaccine wanes over time, ranging from 97% in the first year after vaccination to 84% at 8 years post vaccination.
Breakthrough varicella, which is seen in previously immunized persons, is a well-known clinical entity. [35] The disease course is typically much milder than conventional primary varicella and is characterized by an atypical clinical presentation in which only a few papules or papulovesicles are present, but severe disease with pneumonitis or other organ involvement can occur. Transmission of VZV to other individuals may occur, although at lower rates than in nonimmunized people with primary varicella.
Adverse effects of the vaccination include pain and erythema at the site of injection, allergic reactions to gelatin, and the development of a localized chickenpox. Vaccine-induced herpes zoster infection in immunocompetent and immunocompromised populations has also been reported, though it is a rare phenomenon. Rarer still is the transmission of vaccine-associated virus from vaccinated individuals to susceptible contacts.
Go to Pediatric Chickenpox for more complete information on this topic.
Consultations
For most patients in the pediatric population, a pediatrician can provide treatment. Adults without severe complications can be seen by a primary care physician or internal medicine specialist. In those patients who are immunocompromised, consultation with an infectious disease specialist with knowledge of the most recent pharmacotherapeutic advances is highly advised.
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Dewdrop on rose petal characteristic vesicle of chickenpox. Reprinted with permission from Cutis 65: 355, 2000.
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Vesicular eruption on the trunk demonstrating papules, vesicles, and crusts. Reprinted with permission from Cutis 65: 355, 2000.
