Chickenpox: Detailed Information and Precautions

I. Overview

Chickenpox is a contagious infection caused by the varicella-zoster virus, commonly found in children. It manifests as itchy, fluid-filled blisters on the skin.

II. Age of Infection

• Peak age of infection: 6 months to 7 years old
• The disease can occur at any age, but it is rare in adults.

III. Chickenpox Immunity

After contracting chickenpox, the body develops lifelong immunity to the varicella-zoster virus.

IV. Pregnant Women with Chickenpox

• High risk of fetal varicella-zoster virus (VZV) infection:
  • Mothers who contract chickenpox before or during pregnancy.
  • Mothers who have no chickenpox immunity.
• Risk of birth defects:
  • Mothers who contract the disease in the first trimester, especially during weeks 13-20.
• Risk of newborn babies contracting systemic infection (congenital varicella):
  • Mothers who contract the disease in the 5 days before delivery to 2 days after delivery.
  • Infants are at risk of skin scarring, limb aplasia, eye defects, and developmental delays.

V. Congenital Varicella

• Prevalence: 17-30% of infants with congenital varicella.
• Symptoms: Severe pneumonia, death if treatment is delayed (30%).
• Treatment: VariZIG (immune globulin) and intravenous acyclovir.

VI. Types of Immunity

• Active immunity: Acquired after infection with the varicella-zoster virus or vaccination with a live attenuated vaccine (from 12 years old).
• Passive immunity: Acquired by receiving immune globulin (obtained from individuals who have recovered from the disease).

VII. Chickenpox Complications

a. Common Complications in Children:

• Skin infections: Due to excessive scratching, causing skin damage.
• Increased risk of skin infection when using NSAIDs (pain relievers, fever reducers).

b. Common Complications in Adults:

• Pneumonia: Severe, sudden onset.
• Neurological Complications:
  • Cerebellar ataxia: Occurs after recovery.
  • Encephalitis: During the acute phase.

c. Rare Complications:

• Reye’s syndrome.
• Myelitis.
• Guillain-Barré Syndrome.

d. Other Complications:

• Myocarditis.
• Nephritis.
• Acute pancreatitis.
• Arthritis.
• Orchitis.

VIII. Treatment of Chickenpox

• Treatment Goal: Prevent complications such as pneumonia, neurological disorders, and other complications.
• Medication: Acyclovir (oral or intravenous).

IX. Antiviral Indication

a. Children:

• Children over 12 years old: Antiviral medications are recommended due to the risk of complications similar to adults.
• Children from 12 months to 12 years old:
  • Antiviral medication is indicated if risk factors are present:
    • Close contact with someone who has recently contracted chickenpox.
    • Currently receiving corticosteroid treatment.
    • Currently using aspirin.
    • Chronic skin disease.
    • Chronic heart or lung disease.
• Children under 12 months:
  • Most do not require antiviral treatment unless risk factors are present.

b. Adults:

• Antiviral treatment is recommended for all adults, except pregnant women.

X. Indications for Immune Globulin (VariZIG) Administration

• Exposure to a possible source of chickenpox and:
  • Immunodeficiency without chickenpox immunity.
  • Premature birth/mother without chickenpox immunity.
  • Pregnant women without chickenpox immunity.
  • Newborn infants whose mothers contracted chickenpox in the 5 days before to 2 days after delivery.

XI. Timing and Dosage of Acyclovir

• Timing: From the onset of the first lesion.
  • Normal individuals: Less than 24 hours.
  • Immunodeficiency: Less than 72-96 hours.
• Dosage:
  • Oral: 5 days.
    • Adults: 800mg x 5 times/day.
    • Children: 200mg x 5 times/day.
  • Intravenous: 8-10 days.
    • Adults: 10mg/kg x 8 hours.
    • Children/Pregnant Women: 15mg/kg x 8 hours.
    • Infants: 20mg/kg x 8 hours.

Note:

• This article provides general information about chickenpox.
• Diagnosis and treatment of the disease should be performed by a specialist.
• Always follow the instructions of your doctor and use medication as prescribed.
• Learn more about the chickenpox vaccine to protect yourself and your family.

Source:

• Vietnamese Ministry of Health
• Vietnamese Medical Journal
• Other reputable medical websites.