Within few hours, the contents of each vesicle become turbid, and within 2 to 4 days, a crust forms and separates, leaving a shallow pink depression or erosion. The vesicles typically appear in 3 to 5 crops over the following 2 to 4 days. The lesions are most numerous on the trunk, followed by the face, scalp and limbs. A characteristic feature of primary varicella is the presence of lesions at different stages of development at each site. The total number of lesions is variable.
Vesicles are common in the mouth and other mucous membranes, including the conjunctiva.
Primary varicella in adults has similar clinical features but with more severe constitutional symptoms in evidence. Complications of varicella occur with greater frequency in adults. The diagnosis of primary varicella is typically made easily by the history, clinical presentation, and Tzanck preparation. The differential diagnosis might include other viral exanthems or allergic contact dermatitis in atypical cases. Treatment of primary varicella with oral acyclovir is thought by some to decrease the number of skin lesions and to shorten the duration of the illness, particularly in adults.