That chicken pox is not invariably a mild, uncomplicated exanthem of childhood is better recognized now than it was in the past century, when it was thought that, because of its benign course, the disease was of clinical importance only because it could be confused with smallpox.1The presence of disseminated visceral lesions in varicella neonatorum emphasizes the fact that this may be a severe and even fatal infection.* The commonest complication of chicken pox is secondary bacterial invasion of the skin lesions;4complications due to spread of the virus occur, however, and may produce even more serious problems, particularly since the responsible agent is not susceptible to any of the presently available antibiotic drugs. Involvement of the respiratory tract during the course of chicken pox results either from secondary bacterial invasion or from extension of the viral infection. Pulmonary lesions in varicella have generally been regarded as