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But could regular emollient use from birth actually prevent the development of the condition?
Atopic eczema is a highly pruritic, inflammatory skin condition which affects 20% of children.1 The condition develops during infancy and classically leads to food allergies, asthma and allergic rhinitis in what has been termed the ‘atopic march’.2 A family history of atopic disease is an important risk factor for the development of atopic eczema. In addition, the presence of atopic eczema increases the risk of IgE-mediated food allergies and for example, infants with the condition are six times more likely to develop egg allergies.3 While the precise cause of eczema remains uncertain, the condition is characterised by a defective skin barrier and there is evidence that genetically determined loss-of-function mutations in the gene that codes for filaggrin, a protein that has an important role in skin barrier function, may contribute to eczema development during infancy.4 The presence of defective skin barrier serves as a possible entry route for allergens and this has been proposed as a possible route to sensitisation and the subsequent development of a peanut allergy.5
Emollients are the cornerstone of eczema management and are recommended for all patients with the condition.6 An emollient provides a water impermeable barrier over the surface of the skin which serves to both prevent water loss and ingression of potential allergens and irritants. Given this dual role, is it possible that treatment with emollients soon after birth could actually prevent the development of atopic eczema and the ensuing atopic march? This was the question posed in the barrier enhancement for eczema prevention (BEEP) study published in the Lancet.7 The study was based on the observations of a pilot study undertaken by the same group which found that the incidence of atopic eczema was lower (22% vs 43%) in 124 infants treated with the daily application of an emollient from birth.8 But this was not simply blue sky thinking: several lines of evidence had pointed to a role for emollients in preventing inflammation as well as work which illustrated how the barrier dysfunction in atopic eczema appeared to be a secondary phenomena to subclinical inflammation present in dry atopic skin.9
The BEEP study recruited 1394 high risk (that is, where at least one 1st degree relative had either eczema, allergic rhinitis or asthma) babies who were randomised to either once daily application of an emollient (Diprobase or Doublebase gel) to the whole body excluding the scalp or best practice skin-care advice (the control group). This latter group received advice to use mild cleansers and shampoos specifically formulated for infants but also to avoid soaps, bubble bath and baby wipes.
The primary outcome measure was a diagnosis of eczema at 2 years of age. The results showed no difference: eczema was present at 2 years of age in 23% of infants assigned to daily emollient use and 25% in the control group. There were also no significant differences in the incidence of food allergies or other allergic diseases and the authors were at a loss to explain their findings.
An alternative strategy to reducing food allergies is through early exposure to potentially allergenic foods in order to allow the development of tolerance and this was the subject of the preventing atopic dermatitis and allergies (PreventADALL) study which was also published in the same issue of the Lancet. In PreventADALL, Norwegian researchers explored the dual approach of daily emollient use and early introduction of potential allergic foodstuffs such as peanut butter, wheat porridge and eggs10 and the incidence of eczema was recorded after 12 months. The study had four arms: control (no advice); skin emollients; early feeding and finally combined emollient and early feeding. The incidence of eczema at 12 months was 8% (control group), 11% (emollient group), 9% (food group) and 5% (combined group) and these differences were not significant. In other words, neither a combination of daily emollient use and early introduction of potential allergenic foods reduced the development of atopic eczema at 12 months.
The results of both studies although disappointing, recognise the limited value of these primary prevention strategies. However, these results do not undermine the importance of regular emollient use in the management of established atopic eczema.
Whether changing the composition of an emollient makes any difference remains to be seen and is the subject of the on-going PEBBLES study.11