Using emollient creams to relieve the symptoms of eczema could actually make the condition worse, UK scientists have claimed.

The researchers, based at the University of Bath, have published a study in the British Journal of Dermatology, which shows that the widely available moisturiser, aqueous cream BP, reduces the thickness of healthy skin over a period of four weeks. This, they insisted, calls into question whether the cream should be used for treating eczema.

Eczema is a group of skin complaints that can affect all age groups and can occur anywhere on the body. Symptoms can include an itchy, scaly red rash. According to the Irish Eczema Society, the condition is 30% more frequent now in Ireland than it was in the 1980s - affecting one in five children under the age of seven and one in 12 adults.

Aqueous cream BP is a commonly used emollient cream, which is used to moisturise the skin, improve flexibility and prevent cracking in the protective outer layer of the skin, known as the stratum corneum.

However the cream contains a detergent called sodium lauryl sulphate (SLS), which can increase the permeability of the skin barrier and cause irritation.

The study found that when healthy volunteers applied the cream to their forearms every day for a period of four weeks, the thickness of the stratum corneum was reduced by more than 10%.

The researchers anticipate that using this cream would have an even more dramatic effect on damaged skin, such as that found in eczema.

"The skin has a protective barrier layer of lipids, around one eighth the thickness of a sheet of paper, that stops chemicals from getting into the body and keeps moisture in. SLS is a detergent used to mix oils into water-based moisturisation creams to give a nice creamy texture. It's also used widely in shower gels and other cosmetics.

"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," explained study supervisor, Prof Richard Guy.

The researchers suggested that it might be better for eczema patients to use oil-based ointments on damaged skin.

For more information on eczema, click here