Clinical aspects of chickenpox and herpes zoster.

Chickenpox in immunocompromised individuals is potentially fatal and should be treated with intravenous acyclovir as soon as it is recognized. Data from four double-blind, placebo-controlled trials in the USA provide a sound scientific basis for using acyclovir to treat chickenpox in immunocompetent individuals. Three studies in children and a fourth study in US naval recruits showed statistically significant reductions in the duration of fever, constitutional illness, and time to cutaneous healing, when treatment was initiated within 24 h of rash onset. Although chickenpox is generally mild in children the severity of the disease increases with age and secondary cases in the family tend to be more ill than the primary case. It is recommended that secondary and tertiary cases in a family, and adolescents and adults with chickenpox be treated with acyclovir. In immunocompromised hosts, intravenous acyclovir halts the progression of herpes zoster and is recommended as therapy during new lesion formation. Herpes zoster in otherwise normal hosts is rarely accompanied by visceral dissemination, but carries an increasing risk of post-herpetic neuralgia with increasing age. Published clinical trials have shown a reduction in the duration and severity of acute pain during herpes zoster for patients treated with acyclovir, but results for chronic pain are conflicting with some, but not all, studies showing a beneficial effect.