The possibility of a link between infectious disease morbidity and atopy is not supported by the recently published findings of a large-scale study of 24,341 mother-child pairs in Denmark. Although the data confirmed that larger family sizes, early childcare, pet keeping and farm living correlates with decreased risk of atopic dermatitis in children before 18 months, the results suggested that development of ID in early life is associated with increased, rather than reduced, risk of atopic dermatitis. BMJ 2004;328:1223-6.