Varicella Chickenpox. Varicella Chickenpox is caused by a virus of the herpes group. The disease is highly contagious and is spread by droplet or direct contact. The incubation period for chickenpox ranges from 11 to 21 days. Prodromal symptoms consist of low-grade fever, headache, anorexia, and malaise. On the following day, the characteristic rash begins to appear. The lesions evolve from erythematous macules to form small papules. Quickly, a clear vesicle arises on this erythematous base. The classic lesion of chickenpox has been poetically described as a “dewdrop on a rose petal.” Over the next several days, the vesicles rupture and then crust. The rash begins on the chest and back and spreads centrifugally to involve the face, scalp, and the extremities. New lesions of chickenpox arise in crops over a period of several days.
Varicella-zoster virus infection: herpes zoster in T8 to T10 dermatomes. Typical grouped vesicles and pustules with erythema and edema of three contiguous thoracic dermatomes on the posterior chest wall.