Pathology: Varicella zoster virus is the cause of chickenpox, a usually mild infection that most commonly occurs in childhood.
Aetiology: Chickenpox is spread by droplets of saliva or mucus from the nose and throat. The period of infectivity is typically 1 day before the rash appears until the last spot has crusted over, with the highest risk of infectious occurring in the first 2 days.
Symptoms: Common symptoms prior to the rash's appearance are headache, fever, malaise, sore throat, and myalgia, with the prodrome generally lasting 1-2 days.
Signs: The main sign of chickenpox is a rash of red or pink spots that develops in a centripetal distribution.
Investigations: Microbiology: Swabs of the secretions or vesicles can be taken and analyzed using a PCR for VZV for confirmation.
Treatment: For mild cases of chickenpox, the recommended treatment is simply topical calamine lotion. However, for severe cases, patients may be prescribed antiviral medications such as acyclovir. Aspirin should never be given to children as it may precipitate Reye’s syndrome, which is characterized by encephalopathy and fatty degeneration of the viscera.
Complications: Complications of chickenpox include pneumonitis and reactivation of the virus which can lead to herpes zoster, commonly known as shingles.
Prognosis: The prognosis is generally excellent for uncomplicated cases of chickenpox; however, the risks of complications and mortality increase with age.
Figure 9.3Chickenpox
