It is unclear whether eczema prevalence is truly increasing worldwide.

We sought to investigate worldwide secular trends in childhood eczema.

Children (n = 302,159) aged 13 to 14 years in 105 centers from 55 countries and children aged 6 to 7 years (n = 187,943) in 64 centers from 35 countries were surveyed from the same study centers taking part in Phase One and Three of the International Study of Asthma and Allergies in Childhood by using identical validated and translated questionnaires. Eczema was defined as an itchy, relapsing, flexural skin rash in the last 12 months, and it was termed severe eczema when it was associated with 1 or more disturbed nights per week.

Annual prevalence changes in relation to average prevalence across Phase One and Three were generally small and differed in direction according to the age of the participants and world region. For children 13 to 14 years old, eczema symptom prevalence decreased in some previously high-prevalence centers from the developed world, such as the United Kingdom and New Zealand, whereas centers with previously high prevalence rates from developing countries continued to increase. In the children 6 to 7 years old, most centers showed an increase in current eczema symptoms. Similar patterns to these were present for severe eczema at both ages.

The epidemic of eczema seems to be leveling or decreasing in some countries with previously high prevalence rates. The picture elsewhere is mixed, with many formerly low-prevalence developing countries experiencing substantial increases, especially in the younger age group.