Varicella is a self-limited, benign disease in childhood. When it affects adults, however, serious complications can develop, the most frequent and most dangerous being pneumonia. Adults who develop varicella should be followed closely, with careful attention given to respiratory symptoms in particular, from the first week the rash is evident until it begins to fade. Should pneumonia appear, early start of intravenous acyclovir therapy is indicated in immunodepressed or pregnant patients, or in immunocompetent patients with respiratory problems.