Different types of emollient cream exhibit diverse physiological effects on the skin barrier in adults with atopic dermatitis

Background

Skin barrier dysfunction is a hallmark of Atopic Dermatitis (AD). Despite widespread use, the role of moisturisers in AD development and progression remains unclear.

Objective

To compare the barrier-strengthening properties of a new moisturiser, containing urea and glycerol, to a glycerol-containing moisturiser, a simple paraffin cream (no humectant), and no treatment,

Methods

An observer-blind prospective phase 2 within-subject multilateral single-centre randomised controlled trial in adults with AD (Clinical Trials #NCT03901144). The intervention involved 4-weeks treatment, twice daily, with the 3 products applied to one of 4 areas on the forearms (includes control, randomised allocation). Skin properties (dryness, trans-epidermal water loss [TEWL], hydration and natural moisturising factor [NMF] levels) were assessed before, during and after treatment. The primary outcome was skin sensitivity to the irritant sodium lauryl sulphate (SLS) after treatment.

Results

49 patients were randomised, completed treatment and included in the analysis. The urea/glycerol cream significantly reduced the response to SLS compared to control (-9.0g/m2/h [95%CI -12.562, -5.489] TEWL), paraffin cream (-9.0g/m2/h [-12.602, -5.440] TEWL) and glycerol cream (-4.2g/m2/h [7.760, -0.629] TEWL). Skin moisturisation improved at sites treated with urea/glycerol cream compared to control and paraffin cream, and accompanied by concordant changes in dryness and NMF levels. Subgroup analysis suggested FLG-dependent enhancement of treatment effects.

Conclusion

The urea/glycerol cream strengthened the skin barrier through a mechanism involving increased NMF levels in the skin, and imparted protection from SLS-induced irritation. By helping correct a major pathophysiological process, the urea/glycerol cream has the potential to improve the long-term control of AD.