P C POX

Primary infection with VZV results in varicella (chickenpox), which is typically seen in school-age children in temperate climates in late winter and early spring. Before the varicella vaccine, there were approximately 4 million cases of varicella and 100 varicella-related deaths in the United States per year, whereas after vaccination, the incidence has declined 97%, with no reported pediatric deaths since 2010. Varicella disease presents as a diffuse, pruritic, vesicular rash, with fever and malaise appearing just before or on the day of the rash. The contagious period begins 1 to 2 days before the appearance of the rash and continues until all lesions are crusted, an average of 7 days. The incubation period lasts from 10 to 21 days, with an average of 14 to 16 days. Lesions begin as macules, progressing to papules, then vesicles. Initially, lesions are 2- to 4-mm, thin-walled, irregular vesicles with clear fluid over an erythematous base, classically described as “dewdrops on a rose petal.” The rash usually starts on the head, trunk, and then extremities but can appear anywhere, including mucous membranes. As they resolve, vesicles become umbilicated, fill with cloudy fluid, and develop crust. Lesions in varying stages of healing is a hallmark feature. Healthy, unvaccinated children have an average of 200 to 500 lesions