Aqueous cream damages skin barrier in people with atopic dermatitis
MedWire News: Application of aqueous cream BP to the skin of people with a history of atopic dermatitis (AD) leads to significant skin barrier damage, report researchers.
These findings add to those of another study, previously reported by MedWire News, which demonstrated that corneocyte maturity and size were significantly reduced, and desquamatory and inflammatory protease activity and transepidermal water loss (TEWL) significantly increased following the application of aqueous cream to the skin of volunteers with no history of AD.
In this study, Simon Danby and colleagues, from the University of Sheffield in the UK recruited 13 volunteers with a previous history of AD (symptom free for 6 months) to test the cutaneous effects of aqueous cream BP application.
The cream was applied twice daily to the underside of one forearm for 4 weeks. The other forearm of each participant was used as a control.
The team assessed permeability barrier function and stratum corneum integrity before and after aqueous cream BP application by measuring TEWL and use of tape stripping.
The researchers also enrolled 13 volunteers with current symptoms of AD, who did not apply aqueous cream, to act as controls. Stratum corneum integrity and skin barrier function were also measured in these individuals.
Compared with the untreated control arm, treatment with aqueous cream BP for 4 weeks led to significant elevations in TEWL from baseline. At 4 weeks, TEWL was an average of 24% higher in the treated compared with the control arm, at 12.55 versus 10.11 g/m2/hour.
Tape stripping was carried out to assess the stability of the stratum corneum, with a TEWL measurement of 90 g/m2/hour used as an endpoint to assess skin barrier integrity. In every case, the endpoint was reached significantly sooner on the treated compared with the untreated side.
The researchers note that the volunteers with active AD had significantly higher TEWL measures at baseline than the participants with inactive AD. However, the increase in TEWL brought about by aqueous cream BP application in the participants with inactive AD brought their levels up close to those observed in patients with active disease.
"The negative effects of aqueous cream BP on the skin barrier are most likely associated with the presence of sodium lauryl sulphate (1% w/w)," write Danby and team in the British Journal of Dermatology.
"Aqueous solutions of sodium lauryl sulphate have been shown to cause cutaneous irritation and elevate TEWL at concentrations of 1% and less," they explain.
The authors emphasize that these results and others strongly suggest that aqueous cream BP should not be used or prescribed for treatment of atopic dermatitis or similar conditions.
MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011
By Helen Albert