Chiari malformation

chickenpox A highly infectious viral disease characterized by an itchy rash. Also known as varicella. It is caused by herpes zoster, a member of the herpes family of viruses. Chickenpox has nothing to do with chicken; the name originated to distinguish this mild pox from smallpox (chicken being used, as in chickenhearted, to mean weak or timid). Chickenpox is not a major matter unless it occurs in an immunodeficient person or the pox become infected with bacteria through scratching. Treatment, other than the use of calamine lotion or other topical solutions to diminish itching, is not normally necessary. However, adults (and sometimes children) can have major problems from chickenpox, including pneumonia and encephalitis (inflammation of the brain) that can lead to difficulty with balance and coordination (cerebellar ataxia). Other serious complications can include ear infections, damaged nerves (palsies), and Reye’s syndrome. In such cases, antiviral medications may be tried. Reinfection with chickenpox can occur. Reactivation of the chickenpox virus is responsible for shingles. The current aim in the US is to achieve universal immunization of children with the chickenpox vaccine. See also chickenpox immunization; herpes zoster; neuralgia, postherpetic; shingles.