The latest research
Eczema is a multifactorial inflammatory skin disorder that arises from the interplay of genetic predisposition and environmental factors. It frequently affects infants in the first few months of life and is strongly associated with later development of other allergic disorders, particularly asthma and allergic rhinitis.
Eczema currently affects about 20% of Australian children under two years of age, and it is expected that up to 80% of children suffering with eczema will develop other allergic disease.
While the hygiene hypothesis – where an imbalance between the allergy promoting T-helper 2 (Th2) and non-allergy promoting T-helper 1 (Th1) driven immune responses result from a lack of childhood exposure to infections and microbial components due to increased hygiene practices – is a popular theory behind the steadily increasing rate of allergic disease in western society, not all epidemiological studies fully support this supposition.
The diversity of the gut flora has been found to be significantly reduced in infants with eczema and it has been shown that commensal bacteria belonging to Bifidobacterium and Lactobacillus spp. are present at a significantly greater abundance in non-eczematous infants and children up to five years of age.
Pathogenic bacteria, on the other hand, such as Enterococcus and Shigella spp. have been found to be more abundant in eczematous infants. Swedish researchers have also reported a higher prevalence of S. aureus and C. difficile in children who develop allergic disease.
A number of studies have demonstrated an overall benefit of probiotic supplementation for the prevention of eczema in high risk infants. One such study, a clinical trial performed by the Wilhelmina Children’s Hospital in conjunction with the Wageningen University in the Netherlands, examined the effects of a carefully selected three-strain probiotic combination in 102 women and their offspring who were at high risk of allergic disease. The frequency of eczema, food allergies, allergic rhinitis or asthma were the primary endpoint during two years of follow-up. The probiotic combination consisted of B. bifidum W23, B. lactis W52 (previously classified as B. infantis), and Lactococcus lactis W58.
These three very specific strains were selected on a basis of their capacity to stimulate Th1 and T regulatory cells, inhibit production of Th2 cytokines, and improve gut barrier function.
The formula was administered to the mother during the last six weeks of pregnancy and to the infant for 12 months. Eczema incidence was reported by the parents in a weekly diary during the first three months of life and was significantly lower in the intervention group compared with placebo; 6/50 (12%) vs 15/52 (29%) (P=0.035). The incidence of eczema at one and two years was 23/50 (intervention group) vs 34 (placebo) respectively. Thus, at the age of three months, relative risk reduction was 58%, which decreased to 26% and 22% at one and two years respectively. No differences were observed in respiratory symptoms indicative of asthma or allergic rhinitis at the age of two years.
The study participants were re-evaluated yet again at the age of six. However, this follow-up study showed no statistically significant differences in prevalence of eczema, asthma, allergic rhinitis, and food allergy between the intervention group and the placebo group.
The researchers concluded that one year administration of this selected probiotic combination did demonstrate a beneficial effect on the development of eczema up to the age of two years. Yet, the beneficial effect did not extend to the age of six years and does not lead to primary prevention of asthma.
Based on these results, the research suggests that as the development of the gut microbiota composition may continue for at least the first three years of life, prolonged probiotic therapy may be required to achieve long-lasting impact.
References: FX Medicine Autumn 2017 Vol 85
