Chickenpox

Chickenpox (Varicella) is a highly contagious disease caused by the Varicella-Zoster Virus (VZV), a member of the herpesvirus family.

• Primary infection with VZV usually occurs in childhood, but adults can also be affected.

• Transmission occurs via respiratory droplets or direct contact with vesicular fluid.

• The disease is characterized by a generalized vesicular rash, which progresses from macules to papules to vesicles and crusts.

• Complications are more common in adults, immunocompromised individuals, and pregnant women and may include bacterial superinfection, pneumonia, encephalitis, or hemorrhagic varicella.

Epidemiology:

• Peak incidence in children aged 5–9 years

• Seasonal variation: more common in late winter and early spring

• Vaccine-preventable; the varicella vaccine is effective in reducing incidence and severity

Signs & Symptoms

• Prodromal phase (1–2 days before rash):

  • Mild fever, malaise, headache, fatigue

  • Possible mild anorexia

• Exanthem (rash) phase:

  • Red macular rash appearing first on the trunk, then spreading to face, scalp, and extremities

  • Progression: macules → papules → vesicles → pustules → crusts

  • Lesions occur in crops over several days, giving a varied appearance at the same time

  • Intense pruritus (itching) is common

  • Occasionally regional lymphadenopathy may develop

  • Oral and mucosal lesions: small vesicles in the mouth may cause pain or discomfort while eating

• Resolution phase:

  • Lesions crust and heal in 5–10 days

  • Hyperpigmentation may persist temporarily

Diagnostic Criteria

• Red macular rash with central vesicle

• Lesions present on trunk, oral mucosa, and scalp

• Progression through macules, papules, vesicles, and crusts

• Intense pruritus

• Occasional regional lymphadenopathy

• History of exposure to varicella or lack of prior immunity

Note: Diagnosis is mainly clinical; laboratory confirmation (PCR or serology) is reserved for atypical cases or immunocompromised patients.

Investigation

• Primarily clinical diagnosis

• Laboratory investigations rarely required

• Serology (VZV IgM) for confirmation in uncertain or atypical cases

• PCR testing may be used in immunocompromised patients or for epidemiologic purposes

Treatment

Non-Pharmacological Treatment

• Isolation of patient to prevent transmission

• Maintain skin hygiene to reduce secondary bacterial infection risk

• Cool compresses to relieve itching

• Trim fingernails to prevent excoriation

• Hydration and rest

Pharmacological Treatment

• Antiviral therapy (especially in adults or severe cases):

  • Acyclovir 800 mg orally 5 times daily for 7 days

• Symptomatic relief:

  • Paracetamol 1 g orally every 8 hours for 4–5 days to reduce fever and pain

  • Calamine lotion with 1% phenol applied over the body for 24 hours for 4–5 days to relieve pruritus

Note: Avoid aspirin in children due to risk of Reye’s syndrome

Complications

• Bacterial superinfection of lesions (e.g., Staphylococcus aureus, Streptococcus pyogenes)

• Pneumonia, especially in adults or immunocompromised individuals

• Neurological complications: cerebellar ataxia, encephalitis

• Hepatitis or hemorrhagic varicella in immunocompromised patients

• Pregnancy complications: congenital varicella syndrome

Prevention

• Varicella vaccination:

  • Two doses recommended for children and susceptible adults

  • Reduces severity and incidence of disease

• Avoid exposure for non-immune individuals during outbreaks

• Good hygiene practices to prevent spread (handwashing, covering mouth/nose when sneezing/coughing)