This highly infectious disease, caused by the varicella-zoster virus (VZV), is common in children. Spread is via droplets, saliva and contact with blisters with an incubation period of one to three weeks, infectivity is one to two days before the rash, until lesions are dried and crusted over and lifelong immunity acquired. Prodromal malaise, nausea, headache and fever may precede small, itchy erythematous macules, mainly on the scalp, face, trunk and limbs. These progress to teardrop-like vesicles and pustules which crust over and heal within about one to two weeks. Symptomatic treatment with analgesics may help, with topical calamine lotion and an oral antihistamine to ease the irritation. Complications (pneumonia, encephalitis or dehydration) are rare. Pregnant or breastfeeding women, the immunocompromised and neonates are at greater risk, and may require an additional antiviral agent, specialist advice and hospital admission. At-risk patients in contact with chickenpox can be tested for VZ immunoglogulin (VZIg) antibodies; if non-immune, offer VZIg prophylaxis. A vaccine is available for those at high risk. After chickenpox, shingles may develop in later life. Chickenpox is not a notifiable disease.