People suffering from eczema may have been damaging their skin further by using a recommended cream.
Aqueous cream BP, which is widely prescribed to patients, has been found to reduce the thickness of healthy skin.
Researchers from the University of Bath revealed that a detergent found in the cream called sodium lauryl sulphate (CLS) can reduce the thickness of the skin barrier.
The scientists had healthy volunteers apply the cream to their forearms on a daily basis for four weeks.
Their skin barrier reduced in thickness by more than ten per cent.
Richard Guy, professor of pharmaceutical sciences at the university, commented: "Our study has found that rubbing aqueous cream containing SLS into the skin thins this protective barrier, making the skin more susceptible to irritation by chemicals.
"So to use this cream on eczemous skin, which is already thin and vulnerable to irritation, is likely to make the condition even worse."