The varicella-zoster virus causes varicella (chickenpox) and shingles (herpes zoster). It is very contagious. Chickenpox is usually a childhood infection that begins with a prodrome of fever, headache, and malaise followed by a generalized vesicular rash. It is characterized by the appearance of papules and pruritic vesicles that evolve to pustules and crusts. Lesions typically begin on the face and scalp, spreading inferiorly to the trunk and extremities. In healthy children, chickenpox is self-limited and only requires symptomatic treatment such as lotions and oral antihistamines. Antiviral therapy should be considered for patients greater than 12 years of age, immunocompromised patients, and those with skin disorders or chronic lung disease. Herpes zoster is a painful vesicular eruption that usually occurs in adults. After affecting a patient early in life, the varicella-zoster virus lies dormant in a dorsal root ganglion until reactivation occurs. The rash is unilateral and limited to one or more adjacent dermatomes. Management includes symptomatic treatment and antiviral therapy. Source