Southampton study finds new evidence atopic eczema develops in the womb

Researchers at the University of Southampton have found new evidence that atopic eczema develops before birth and is linked to a child’s growth in the womb and shortly after birth.

The study was led by Dr Sarah El-Heis and presented at the British Association of Dermatologists’ Annual Meeting in Edinburgh last month where it won the Martin Beare Paediatric prize.

Atopic eczema is a very common skin condition due to skin inflammation. It may start at any age, but the onset is often in childhood. One in five children in the UK is affected by eczema at some stage. It may also start later in life in people who did not have it as a child.

The study found that infants with eczema demonstrated altered patterns of growth during pregnancy, including impairment in growth of length starting in early pregnancy, prior to eczema becoming evident. The findings suggest that growth is impaired prior to the start of the disease process and its treatment, and that there are important influences acting during pregnancy on this common skin condition.

Within the Southampton Women’s Survey, a mother-offspring study, 1759 infants had serial measurements of their length, head and abdominal circumference during pregnancy at 11, 19 and 34 weeks, at birth, and at ages 6 and 12 months, and were assessed for eczema at ages 6 and/or 12 months.

Evidence of faltering growth in length from 11 weeks of pregnancy and shorter femur length, smaller abdominal circumference and a higher head to abdominal circumference ratio at 34 weeks’ gestation were associated with 20 per cent or greater increased risks of eczema at age six months. Infants who had had a larger head circumference in early pregnancy and a declining abdominal growth velocity from 19 to 34 weeks of pregnancy had a 33 per cent greater likelihood of eczema at age 12 months.

One possible explanation for these findings are “brain sparing” responses where the growth of the head and brain takes priority over the growth of the rest of the body. One organ that could be affected is the thymus, which is important in regulating the immune system, and this could result in an imbalance in immune cells and chemicals producing the inflammatory response seen in atopic eczema.

Dr El-Heis, the study’s lead researcher from the University of Southampton and the Medical Research Council Lifecourse Epidemiology Unit, said: “Infants with eczema have an increased risk of impaired growth, which is a clinical concern that underpins recommendations to monitor growth in all infants with eczema. A number of reasons for the impaired growth have been proposed and include effects of the inflammatory process, topical corticosteroid treatment or an inappropriately restrictive diet. However, we have shown that infants with eczema at age six and 12 months have altered growth patterns before they are born and before eczema becomes evident, suggesting that there are important influences acting during pregnancy.”

Nina Goad, of the British Association of Dermatologists, said: “Research into this common disorder has taken some interesting turns in recent years, with discoveries relating to birthweight, maternal socioeconomic status and even maternal mood during pregnancy impacting on risk factors. What is becoming clear is that there is no one, simple answer to why some babies develop eczema, and instead there is a complex interplay of factors, some of which are genetic and some of which are environmental. This study provides more data to help scientists explore the possible causes and how they may relate to one another.”

For more information on eczema, see the British Association of Dermatologists’ Patient Information Leaflet.