Facial scarring after varicella. A comparison with variola major and variola minor.

To assess the prevalence of persistent facial scars after recovery from chickenpox (varicella), 250 subjects in Somalia in whom the diagnosis had been confirmed by electron microscopic identification of varicella virus were examined in 1979, a year after their illness; 2.4% had five or more facial scars indistinguishable from those seen among smallpox (variola major or variola minor) victims, with a higher percentage among males (2.7%) than females (1.9%). The highest proportion of those with five or more residual facial scars (8.3%) was found among young adults 20-29-years-old. The low proportion of varicella cases who had five or more facial scars contrasts with the 6.8% of cases of variola minor who were similarly scarred one year later (Somalia, 1978), and to an even greater degree with the situation after variola major, where the proportion varied from 65% for vaccinated subjects to 85% among unvaccinated persons (India, 1976). Pockmark surveys are a valid method for determining the past occurrence of variola major but cannot be relied on in areas were variola minor has occurred. However, varicella must be considered when making such a retrospective diagnosis.