Skin bacteria

The effectiveness of skin as a barrier is important in eczema. Bacteria, the type called Staphylococcus aureus are commonly found on the skin of people with eczema. .

Staphylococcus aureus is capable of producing a protein, called a superantigen, that is very potent at activating the immune system locally. This leads to reactions within the skin that further damage the barrier effect of the skin, which makes it easier for bacteria to penetrate the skin, and so the vicious cycle goes on.

Skin barrier function

Exactly why eczema has become more common over the past few decades is unclear but the increase is mirrored in other allergic conditions such as asthma.

In terms of eczema the increased use of soaps for washing may trigger an initial breakdown of skin barrier function in susceptible individuals, particularly in children.

The top layer of skin cells is the most important layer in the effectiveness of the barrier. Here the individual cells overlie each other, preventing bacteria from breaking down the water-holding properties of the skin.

Fatty substances (lipids) are secreted by the cells. These lipid molecules create a tough connecting network, acting as the mortar to create the barrier.

The levels of lipids within the skin layers are known to be reduced in eczema. This might partly be due to excess removal through repeated washing with soaps. The drop in lipid content creates shrinking of the skin cells, thus opening up cracks between them. These cracks allow bacteria to get between the cells, thus triggering the immune system.

Emollients

Emollients are soap substitutes which help to re-hydrate the skin. By putting a moisture-retaining layer on the surface the internal moisture of the skin is retained. The emollient penetrates to an extent between the skin cells and substitutes for the deficient amounts of lipid.

To be maximally effective emollients need to be applied three or four times a day is the minimum.

The most intense form of emollient treatment is the so-called wet wrap technique.

Following a bath to which has been added an emollient oil the person applies a thick layer of emollient to coat the skin. On top of that is applied a wet layer of cotton dressing, which is then covered with a dry layer of the same dressing. This technique, although messy and time consuming, rapidly improves the barrier effect of the skin.

As with all eczema treatments the effect is of course only temporary. This happens also through the reduction in the amount of itch that occurs in skin that’s been well treated with emollients.

Scratching

Scratching leads to activation of the immune system. The medical term for these compounds is ‘inflammatory mediators’. This sets up the ‘itch-scratch cycle’, which leads to scratching, which releases inflammatory mediators, which exacerbate the eczema and on it goes.

Use of emollients

Emollients are thought of as passive or low-grade treatments. This seems now to be incorrect, as there is increased evidence that using emollients well and often also dampens the immune reactions within the skin that contribute to eczema.

Emollients are safe and cheap and it therefore makes a lot of sense to find a range that suits you and to use them as often as you can.