Varicella is the highly contagious primary infection caused by varicella-zoster virus. It is characterized by successive crops of pruritic vesicles that evolve to pustules, crusts, and at times, scars. This infection is often accompanied by mild constitutional symptoms; the primary infection occurring in adulthood may be complicated by pneumonia and encephalitis.
Causes of Varicella
- Varicella’s cause, the varicella-zoster virus, is a member of the human herpesvirus subfamily Alphaherpesvirinae and, as is true of all herpes viruses, is a deoxyribonucleic acid (DNA) virus.
- Varicella is highly contagious; secondary attack rates range from 80-90% for household contacts.
- Human (alpha) herpesvirus 3 (V-Z virus), a member of the herpesvirus group, is responsible for the development of varicella.
- Direct person-to-person contact with lesions and/or airborne droplets spreads the V-Z virus. Neonatal varicella is caused by maternal viremia, leading to spread of the virus across the placenta.
- Risk factors no prior history of varicella, unvaccinated status, immunosuppression.
Symptoms of Varicella
Chickenpox causes a red, itchy rash on the skin that usually appears first on the abdomen or back and face, and then spreads to almost everywhere else on the body, including the scalp, mouth, nose, ears, and genitals. The rash begins as multiple small, red bumps that look like pimples or insect bites. They develop into thin-walled blisters filled with clear fluid, which becomes cloudy. The blister wall breaks, leaving open sores, which finally crust over to become dry, brown scabs. Some children have a fever, abdominal pain, sore throat, headache, or a vague sick feeling a day or 2 before the rash appears. These symptoms may last for a few days, and fever stays in the range of 100°–102° Fahrenheit (37.7°–38.8° Celsius), though in rare cases may be higher. Younger kids often have milder symptoms and fewer blisters than older children or adults.
Diagnosis
Usually made on clinical findings alone.
Treatment
Symptomatic therapy Directed at reducing pruritus.
- Lotions Application gives short-term relief of pruritus.
- Caution re antipyretic agents Antipyretic administration is of concern because of a possible link between aspirin and Reye’s syndrome in children with varicella.
Antiviral agents
- Otherwise healthy patientsIf begun within 24 h after onset of varicella, decreases the severity of varicella and reduces secondary cases.
- Acyclovir 20 mg/kg (800 maximum) qid for 5 days
Treatment of bacterial superinfection Directed at S. aureus and/or group A streptococcus.
- Mupirocin ointment Applied twice daily to lesions.
- Oral antibiotics
Prevention
- Immunization VZV immunization is now available (Varivax) and is 80% effective in preventing symptomatic primary VZV infection. 5% of newly immunized children develop rash. Those at high risk for varicella, who should be immunized, include: normal VZVnegative adults, children with leukemia, and immunocompromised individuals (immunosuppressive treatment, HIV infection, cancer). VZV vaccine results in both cell-mediated immunity and antibody production against the virus. Immunization with VZV vaccine may boost humoral and cell-mediated immunity and decrease the incidence of zoster in populations with declining VZV-specific immunity.
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