Snapshot A 3-year-old girl is brought to the urgent care clinic for a rash. She attends daycare, where several other children had a similar rash and fever about 2 weeks ago. The patient began having a fever last night, and the itchy rash erupted this morning on the head and chest. On physical exam, she has multiple vesicles on her face, chest, and back, as well as excoriations from scratching. The mom is reassured, and the physician informs her to keep the patient away from other children while she is contagious. Introduction Classification varicella-zoster virus (VZV) an enveloped, linear double-stranded DNA virus also known as human herpesvirus-3 transmitted via respiratory secretions direct contact with skin lesions causes chickenpox, herpes zoster (shingles), encephalitis, meningitis, and pneumonia Prevention chickenpox live vaccine adults and children 1 year or older Epidemiology Demographics chicken pox in children encephalitis and pneumonia in the immunocompromised Risk factors immunosuppression sick contacts ETIOLOGY Pathogenesis the virus infects T-cells the virus can become latent in the dorsal root ganglia or trigeminal ganglia reactivation of the latent virus causes herpes zoster often precipitated by immunocompromise or stress Presentation Symptoms fever and malaise Physical exam asynchronous vesicular rash very itchy but not painful starts on the head and trunk and spreads to the extremities eventually develops a crust Studies Labs Tzanck smear positive if multinucleated giant cells are seen polymerase chain reaction direct fluorescent antibody staining Differential Herpes simplex virus distinguishing factor typically does not present in a dermatomal fashion Contact dermatitis distinguishing factor typically is more itchy than painful DIAGNOSIS Making the diagnosis most cases are clinically diagnosed in atypical cases, laboratory examination may be useful Treatment Management approach for chickenpox, treatment is centered around symptomatic relief Conservative soothing creams indication immunocompetent patients with chickenpox Medical oral antivirals indications immunocompromised patients with chickenpox drugs valacyclovir famciclovir acyclovir analgesics indication all patients drugs do not give aspirin for risk of Reye Syndrome Post-exposure prophylaxis patients with immunity (e.g., completed age-appropriate VZV vaccinations or documented history of varicella infection) no prophylaxis recommended patients with incomplete vaccination immunocompetent varicella vaccine immunocompromised, pregnant, or other contraindications to varicella vaccination varicella immune globulin Complications Disseminated disease in immunocompromised patients often involves the viscera Cutaneous scarring Prognosis Chickenpox is often self-resolving in children