Aspects of eczema in childhood

Abstract

Eczema (atopic dermatitis) is a common itchy inflammatory skin disease that often starts in childhood. Having eczema is troublesome and has been shown to reduce quality of life. Eczema is associated with an increased risk for other allergy-related diseases such as asthma and rhinitis. Knowledge co ncerning the natural course of eczema and its association with asthma and rhinitis in childhood is limited. Even though a majority of children with eczema have mild disease, most studies on quality of life and associations with asthma and rhinitis have bee n done in selected populations of children with moderate to severe eczema. New knowledge about eczema genetics and skin barrier function has highlighted the need for longitudinal studies to better understand the natural course of eczema as well as its association with eczema, asthma and rhinitis.

The aim of this epidemiological study was to provide a better understanding of childhood eczema in the general population and especially its association with asthma and rhinitis. We used the population-based birth cohort BAMSE, including 4,089 children followed up at age 0, 1, 2, 4, 8 and 12 years with parental questionnaires focusing on symptoms of allergy-related diseases and risk factors.

In paper I we showed that allergy-related diseases affect a majority of children during the first 12 years of life and that eczema, asthma and rhinitis develop dynamic ally throughout childhood. In addition we found that comorbidity between allergy-related diseases increase with increasing age and that 7.5% of 12-year-old children have two or three of the diseases eczema, asthma and rhinitis.

In paper II we examined eczema severity at 12 years in relation to asthma, rhinitis and Filaggrin mutations. We found that the risk of having asthma and rhinitis was associated with eczema severity, with the highest risk among boys with moderate to severe eczema. However, no association between Filaggrin mutations and severity of eczema was found.

In paper III we showed that eczema and even mild eczema among pre-adolescent girls is associated with impaired self-perceived health. Finally, in paper IV we examined prognosis and risk factors for eczema, asthma and rhinitis in pre-adolescence among children with infantile eczema. We found that a lmost half of the children with infantile eczema will have eczema, asthma or rhinitis in pre-adolescence but in three of four children the eczema will have remitted. We also found that e czema in the first but not the second year of life is associated with a good prognosis for eczema but an increased risk of asthma and rhinitis in pre-adolescence.

In conclusion the results of this thesis stress the importance of allergy-related diseases and in particular eczema among children as a public health concern. This thesis also demonstrates a strong association between eczema, asthma and rhinitis in childhood and emphasizes the importance of considering comorbidities between these diseases both in research and in clinical practice.