Pediatric Chickenpox Treatment & Management

Manage pruritus in patients with varicella with cool compresses and regular bathing. Discourage scratching to avoid scarring. Trimming the child’s fingernails and having the child wear mittens while sleeping may reduce scratching.

Warm soaks and oatmeal or cornstarch baths may reduce itching and provide comfort. Topical calamine lotion may produce caking of lesions and excessive drying of the skin, causing the child to scratch. Oral antihistamines, such as diphenhydramine and hydroxyzine, are used for severe pruritus. Caution must be used with topical diphenhydramine; toxicity may occur from systemic absorption if it is applied to the entire body.

Because of the association of varicella and aspirin therapy leading to Reye syndrome, acetaminophen is recommended for use for the reduction of fever. Studies have also tried to find an association between ibuprofen and risk of fasciitis; the results have not been conclusive.

The routine use of acyclovir or valacyclovir in healthy children is recommended by the AAP if it can be given within 24 hours after the rash first appears in children older than 12 years, those with chronic cutaneous or pulmonary disorders, those on long-tern salicylate therapy, and children receiving corticosteroids. ^[31] Intravenous acyclovir is recommended only for the treatment of varicella in immunocompromised children or in healthy children with varicella pneumonia or encephalitis.

In some instances, acyclovir may be considered for teenagers and adults with otherwise uncomplicated varicella. Additionally, antiviral therapy should be considered for patients with recent steroid use or those with extensive eczema.

A UK study that compared acyclovir with varicella zoster immune globulin (VZIG) as postexposure prophylaxis in children with cancer found similar rates of breakthrough infections. Clinical varicella occurred in 6.0% of the acyclovir group and in 11.1% of the VZIG group. ^[32]

Varicella zoster immune globulin (VariZIG by Cangene) was approved by the FDA in December 2012. It is indicated for high-risk individuals within 10 days (ideally within 4 days) of chickenpox exposure. This agent reduces complications and the mortality rate of varicella, not its incidence. It is used as postexposure prophylaxis in high-risk individuals; for immunologically normal patients, postexposure prophylaxis using varicella vaccine is preferred. ^[33] High-risk groups include the following:

• Immunocompromised children and adults

• Newborns of mothers with varicella shortly before or after delivery

• Premature infants

• Infants less than one year of age

• Adults without evidence of immunity

• Pregnant women

VariZIG is administered intramuscularly, never intravenously. The dose is 125 U/10 kg body weight. Administration as soon as possible after exposure is best, but it can prevent or attenuate varicella if administered within 10 days (ideally within 96 hours) of contact. The expected duration of protection is approximately 3 weeks.

Intravenous immunoglobulin (IVIG) has been used to prevent varicella after exposure when VariZIG is not available. Clinical efficacy is not exactly known. Patients already on replacement IVIG do not need VariZIG if their most recent IVIG infusion was within 3 weeks.

When maternal varicella has developed within 5 days before or 2 days after delivery, neonatal varicella is likely to be severe and disseminated. Prophylaxis or treatment is required with VZIG and acyclovir. Without these drugs, mortality rates may be as high as 30%. The primary causes of death are severe pneumonia and fulminant hepatitis.

If the onset of maternal varicella is more than 5 days ante partum, a full-term neonate will usually have only mild varicella. Treatment with VZIG is not recommended in such cases, but acyclovir may be used, depending on individual circumstances.

A high level of suspicion is necessary for early recognition and timely appropriate treatment of secondary infections. Suspect secondary infection if systemic manifestations do not improve in 3-4 days, the fever returns or worsens, or the child’s condition deteriorates after initial improvement. Suspicion of secondary bacterial infection should prompt early institution of empirical antibiotic therapy until the results of culture studies become available.

Varicella vaccine consists of live attenuated Oka strain varicella virus. The vaccine is safe and highly immunogenic. It was approved for use in the United States in 1995 and has greatly reduced the incidence and mortality due to varicella. ^[7] The vaccine has a protective efficacy of 71-100% against varicella. However, it affords a much greater degree of protection against moderate and severe varicella (95-100%). ^[34]

Babies are born with protective maternal antibodies to varicella. The half-life of these antibodies is about 6 weeks, and most children have very low levels beyond age 5 months. ^[35] However, the varicella vaccine is recommended after age 1 year. A single dose provides protection to approximately 85% of recipients. Vaccine-conferred immunity to varicella wanes over time, making more vaccine recipients susceptible to the disease.

The Advisory Committee on Immunization Practices (ACIP) and the American Academy of Pediatrics (AAP) recommend 2 doses of this vaccine for all children. ^{[36, 6, 37]} After the first dose at age 12-15 months, the second should be administered at age 4-6 years. All persons who have received one dose at any time in the past should be offered a second dose. Two doses of the vaccine provide 98% protection against varicella and 100% protection against severe disease. ^[6] These children also have a lower incidence of breakthrough varicella. ^[34]

A study by Su et al reported that pyrexia, headache, or vomiting occurred in 494 (3%) out of 14,641 adverse events after second-dose vaccination. No new or unexpected safety concerns for second-dose varicella vaccination were found. ^[38]

Breakthrough disease involves varicella that occurs after 42 days of immunization. When it occurs, it is usually mild disease but can spread to other susceptible individuals. These children usually have less than 50 skin lesions, and fever is low and quickly subsides. Headache, sore throat, malaise, and anorexia are less frequent. ^[39]

Some studies have found that breakthrough disease is more common if the vaccine was given prior to age 14 months, within 28 days after the measles-mumps-rubella (MMR) vaccine, and if the child was on oral steroid therapy. ^[40] Duration between vaccination and exposure has also been found to be significant. ^[41] Other studies have not found such associations. ^[39]

Research study protocols allow varicella vaccine administration to patients with leukemia while they are in remission. Seroconversion is good among children with leukemia. ^[42]

Even with high levels of vaccination, varicella outbreaks do occur. Outbreaks can be controlled by offering catch-up vaccination to unimmunized children and adolescents in the area. ^[43] Postexposure prophylaxis with the vaccine, if provided within 36-72 hours of contact, can prevent or attenuate disease in the exposed individual. ^[44] Although vaccinated children develop milder disease, they are still infectious.

The combined MMRV vaccine (Varivax) has been shown to be associated with an increased risk of febrile seizure occurring 5-12 days following vaccination at a rate of 1 in 2300-2600 in children aged 12-23 months compared with separate MMR vaccine and varicella vaccine administered simultaneously. ^{[45, 46]} As a result, the CDC Advisory Committee on Immunization Practices (ACIP) recommends that separate MMR and varicella vaccines be used for the first dose, although providers or parents may opt to use the combined MMRV for the first dose after receiving counseling regarding this risk. ^[47] MMRV is preferred for the second dose (at any age) or the first dose if given at age 48 months or older.

It is estimated that there is a slightly higher risk of febrile seizures in children aged 12-23 months vaccinated with the MMRV when compared with separate MMR and varicella vaccine administration. The period of risk for febrile seizures is from 5-12 days after receipt of the vaccine. However, there is no increased risk of febrile seizures among patients aged 4-6 years receiving the MMRV. Thus, the American Academy of Pediatrics recommends that either MMR and varicella vaccines separately or the MMRV be used for the first dose of measles, mumps, rubella, and varicella vaccines administered at age 12-47 months. For the first dose of measles, mumps, rubella, and varicella vaccines administered at ages 48 months and older, and for dose 2 at any age (15 mo to 12 y), use of MMRV is preferred. ^[48]

Data from postlicensure studies do not suggest that children aged 4-6 years who received the second dose of MMRV vaccine had an increased risk for febrile seizures after vaccination compared with children the same age who received MMR vaccine and varicella vaccine administered as separate injections at the same visit. ^[47]  

Another study by Marin et al that examined postlicensure estimates of varicella vaccine effectiveness among healthy children reported that one dose of varicella vaccine was moderately effective in preventing all varicella and highly effective in preventing moderate/severe varicella, with no differences by vaccine. The study also added that the second dose adds improved protection against all varicella. ^[49]

Children who develop severe and life-threatening varicella complications may require hospitalization in an intensive care unit (ICU). The following findings are indications for admission to the ICU:

• Altered consciousness

• Seizures

• Difficulty walking

• Respiratory distress

• Cyanosis

• Low oxygen saturation

Hospitalize and treat all newborns whose mothers developed varicella less than 5 days before or within 2 days after delivery. Inpatient care of varicella requires strict isolation from other patients and susceptible healthcare workers. A negative pressure room is ideal.

Most cases of hospitalized uncomplicated varicella do not require transfer to a tertiary care pediatric facility. However, immunocompromised children with varicella may develop significant morbidity and mortality and should be transferred to a tertiary care pediatric center. Similarly, patients with complications of varicella, such as pneumonia, encephalitis, or severe skin manifestations such as necrotizing fascitis, should be transferred to a tertiary pediatric facility.

Advise parents to provide a full and unrestricted diet to the child. Some children with varicella have reduced appetite and should be encouraged to take sufficient fluids to maintain hydration. Adequate hydration is especially important if the child is receiving acyclovir because the drug can crystallize in the renal tubules if administered to dehydrated individuals.

The AAP recommends excluding affected children from school until the sixth day of rash. ^[36] However, this may not prevent spread of varicella, because the child is infective before the rash appears. Children with chickenpox should avoid nonimmune pregnant women, unimmunized young infants, and others with immunodeficiencies or who are taking prednisone long term. No other activity restrictions are needed for young children with uncomplicated varicella.

Consult with an infectious disease specialist in the following situations:

• Progressive or severe varicella

• Life-threatening complications (eg, encephalitis, pneumonia)

• Serious secondary bacterial infections, especially group A streptococcal superinfections, which may evolve rapidly into necrotizing fasciitis and toxic shock syndrome