What is the overview of Varicella (chickenpox)?

From the Guidelines

Chickenpox is a highly contagious viral infection that can be effectively prevented with a two-dose varicella vaccine schedule, as recommended for children at 12-18 months with a booster at 4-6 years, providing protection from severe chickenpox 1.

Overview of Chickenpox

Chickenpox is caused by the varicella-zoster virus, characterized by an itchy rash of fluid-filled blisters that appears 10-21 days after exposure. The disease typically affects children but can occur at any age, with symptoms including fever, fatigue, headache, and loss of appetite before the rash develops.

Treatment and Management

Treatment focuses on symptom management with:

• Acetaminophen for fever (avoid aspirin in children due to Reye's syndrome risk)
• Antihistamines like diphenhydramine (Benadryl) for itching
• Keeping the skin clean to prevent secondary bacterial infections
• Calamine lotion, cool baths with baking soda or colloidal oatmeal, and loose-fitting clothing can help relieve discomfort In severe cases or for high-risk individuals, antiviral medications like acyclovir (800mg five times daily for 7-10 days for adults) may be prescribed if started within 24 hours of rash onset.

Prevention

Prevention is available through the varicella vaccine, with a two-dose schedule providing better protection against severe chickenpox than a single dose 1. The virus spreads through direct contact with blisters or through airborne droplets, and infected individuals remain contagious until all blisters have crusted over, typically requiring isolation for 5-7 days after rash onset.

Key Recommendations

• Two doses of varicella vaccine are recommended for children at 12-18 months with a booster at 4-6 years 1
• Unvaccinated adults and children should be screened for susceptibility to primary infection, and seronegative immunocompetent patients with inflammatory bowel disease (IBD) should receive two doses of varicella vaccine, a month or more apart, completing the course at least 3 weeks before any immunomodulators are started 1

From the FDA Drug Label

Chickenpox: Acyclovir tablets is indicated for the treatment of chickenpox (varicella). Treatment of Chickenpox: Children (2 years of age and older):20 mg/kg per dose orally 4 times daily (80 mg/kg/day) for 5 days. Children over 40 kg should receive the adult dose for chickenpox Adults and Children over 40 kg: 800 mg 4 times daily for 5 days. Chickenpox in otherwise healthy children is usually a self-limited disease of mild to moderate severity. Adolescents and adults tend to have more severe disease

Chickenpox Overview:

• Definition: Chickenpox is a disease caused by the varicella-zoster virus.
• Treatment: Acyclovir is indicated for the treatment of chickenpox.
• Dosage: The dosage of acyclovir for chickenpox is 20 mg/kg per dose orally 4 times daily for 5 days in children (2 years of age and older), and 800 mg 4 times daily for 5 days in adults and children over 40 kg.
• Severity: Chickenpox is usually a self-limited disease of mild to moderate severity in healthy children, but adolescents and adults tend to have more severe disease 2, 2, 2.

From the Research

Overview of Chickenpox

• Chickenpox, also known as varicella, is a highly contagious virus caused by the varicella zoster virus (VZV) 3, 4.
• The primary infection of VZV causes varicella, which may reactivate years later to cause herpes zoster (HZ or shingles) 3.
• After shingles heal, patients may develop post-herpetic neuralgia (PHN), a neuropathic pain syndrome that can cause significant suffering for years and is often refractory to treatment 3.

Causes and Risk Factors

• VZV infection can be severe in immunocompromised individuals, infants, and adults 4.
• The risk of developing complications from VZV infection is higher in certain groups, such as those with weakened immune systems, pregnant women, and premature infants 5.

Treatment and Management

• Antiviral therapy, such as acyclovir, valacyclovir, and famciclovir, can effectively treat acute varicella and HZ 3, 6.
• The use of vaccines, such as the varicella vaccine and the HZ vaccine, can prevent varicella and reduce the risk of developing HZ and PHN 3, 4, 6.
• New molecules, such as valnivudine hydrochloride and valomaciclovir stearate, are being developed as potential anti-VZV candidates 6.

Complications

• Post-herpetic neuralgia (PHN) is a common complication of HZ, which can cause significant pain and suffering for years 3, 4.
• Other complications of VZV infection include myelitis, cranial nerve palsies, meningitis, stroke, retinitis, and gastroenterological infections such as ulcers, pancreatitis, and hepatitis 4.