Risk of developing asthma in young children with atopic eczema: a systematic review.

BACKGROUND: It is commonly believed that the majority of infants and young children with early atopic eczema will develop asthma in later childhood. This belief is mainly based on cross-sectional population studies. Recent evidence suggests a more complex relationship between early eczema and asthma.

OBJECTIVE: This systematic review was conducted to assess the risk of developing asthma in children with atopic eczema during the first 4 years of life.

METHODS: A sensitive search was performed to identify all prospective cohort studies on the topic. By pooling the eligible reports, we calculated the risk of developing asthma at 6 years of age or older in children with atopic eczema in the first 4 years of life.

RESULTS: Thirteen prospective cohort studies were included, with 4 representing birth cohort studies and 9 representing eczema cohort studies. The pooled odds ratio for the risk of asthma after eczema, compared with children without eczema, in birth cohort studies was 2.14 (95% CI, 1.67-2.75). The prevalence of asthma at the age of 6 years in eczema cohort studies was 35.8% (95% CI, 32.2% to 39.9%) for inpatients and 29.5% (95% CI, 28.2% to 32.7%) for a combined group of inpatients and outpatients.

CONCLUSION: Although there is an increased risk of developing asthma after eczema in early childhood, only 1 in every 3 children with eczema develops asthma during later childhood. This is lower than previously assumed.

CLINICAL IMPLICATIONS: Our results may have important consequences for counseling patients with atopic eczema and their parents.