Carroll WD, Lenney W, Child F, et al. Arch Dis Child. 2006;91:405–409 PURPOSE OF THE STUDY. The term “atopy” can refer to allergic conditions such as allergic rhinitis, asthma, eczema, and food allergy, which cluster in families. It can also be defined as the tendency to generate an immunoglobulin E (IgE) response to specific allergens. Is there a relationship between such IgE responses and the severity of asthma? STUDY POPULATION. The study included 400 children (aged 7–18 years) with asthma (documented episodes of wheezing in the previous 12 calendar months and physician diagnosis). METHODS. Patients completed a standardized observer-administered International Study of Asthma and Allergies in Childhood questionnaire and underwent baseline spirometry, skin-prick testing (SPT) to dust mites, grass mix, cat, dog, cockroach and Alternaria, and measurement of total serum IgE level. Atopy was defined as at least 1 SPT wheal >3 mm or a total serum IgE level of >100 IU/mL. RESULTS. Total IgE was associated with increased asthma-severity score, decreased forced expiratory volume in 1 second (FEV1) (mean IgE with FEV1 < 80% predicted: 812; mean IgE with FEV1 > 80%: 449), and risk of hospital admission (mean IgE with hospitalization in last year: 726; no hospitalization: 392). Increasing skin-prick–test reactivity was associated with increased risk of hospital admission (mean sum of SPT wheals with hospitalization in last year: 12.1 mm; no hospitalization: 6.5 mm). CONCLUSIONS. In children with asthma, increasing atopy is associated with increasing asthma severity. REVIEWER COMMENTS. The majority of children with asthma have allergy, and the more allergy they have, the worse their asthma is. This is almost certainly a causal relationship; not surprisingly, inhaling things to which you are allergic can worsen your asthma. This reinforces the importance of assessing the allergic status of all children with asthma and reducing the exposure for those whose allergies are amenable to environmental control (dust mites, furry pets, mold, and cockroach).