All of the following are true about Chickenpox except:
Incubation period can range from 10-21 days.
Subclinical varicella is rare
Simultaneous presence of lesions in various stages of evolution is characteristic
Umbilicated vesicles are the earliest lesions to appear
d. Umbilicated vesicles are the earliest lesions to appear(Ref: Nelson 20/e p1580-1581)Initial exanthem in Chicken pox consists of pruritic erythematous macules that evolve through papular stage to form clear, fluid- filled vesicles. Clouding & umbilication of the lesions begin in 24-48 hr.Simultaneous presence of lesions in various stages of evolution is characteristic of varicella.Distribution of rash is predominantly centripetal with greatest concentration on trunk.
General Considerations - Infectious Diseases