Lack of efficacy of humidification in the treatment of croup: Why do physicians persist in using an unproven modality?

Abstract

Humidification is a time-honoured therapy for childhood croup (acute laryngotracheobronchitis). Despite a paucity of evidence supporting its use, many physicians, nurses and parents still apply this treatment. Our objective was to summarize available evidence and assess the rationale for the ongoing use of humidity to treat childhood croup. Searches of both MEDLINE and the Cochrane Database were conducted for English-language original or review literature on the treatment of croup with humidity, for the years 1966-1999. Only 2 published studies have attempted to evaluate humidification therapy for croup, and none has been published since 1984. There is no published evidence to support the commonly held empirical view that humidity helps alleviate the symptoms of childhood croup, and no understanding of which factors of moisture or temperature affect patient outcomes. Risks may include scalding and unnecessary discomfort. There is no strong evidence supporting the use of humidity in the treatment of croup. Although such treatment is still widely used, it is not without risk, and further trials are required to address its efficacy.