La varicella

Abstract

This is a review of varicella, its complications and management. Varicella is very contagious and more than 90% of cases occur in individuals younger than 15 years of age. The average incubation period is 14 days, transmission occurs via contact with aerosolised droplets from nasopharyngeal secretions of an infected individual. The period of infectivity is generally considered to last from 48 hours prior to the onset of rash until skin lesions have fully crusted. Secondary bacterial infection or varicella lesions are the most common complications. Necrotizing fasciitis and the toxic shock syndrome, due to Staphylococcus aureus or Streptococcus pyogenes are the most severe complications. Viral dissemination and varicella pneumonia are more common in adults, with a reported incidence of about 1/400 cases. Risk factors linked to the development of varicella pneumonia include cigarette smoking, pregnancy, immunosuppression and male gender. Neurological complications associated with varicella are cerebellar ataxia (an immunologically mediated demyelinating process) and encephalitis, the pathogenesis of which is not completely understood. Post-exposure prophylaxis with Varicella-Zoster Immune Globulins is still recommended in immunocompromised children, susceptible pregnant women, newborn infant and premature infants. Before antiviral drugs were available, 30% of children with malignancies developed disseminated varicella and infection was fatal in 7-17% of cases.