“Don’t scratch, you’ll only make it worse”; how often have you heard yourself speak that phrase, to no effect. Apparently telling an eczema sufferer not to scratch doesn’t work. They simply can’t help it. Why not?

Why does eczema itch?The answer to this dilemma lies in the nature of the dead horny outer layer of skin, and how it is made. It is called the cornified cell envelope by scientists, CCE. Living cells are bound together in the skin by cell junctions, and as they come to the surface, they flatten and form into dense flat and filament shapes which usually interlock. However, being dead cells, they require a kind of protein glue called filaggrin to hold them together into an impenetrable shield, keeping out fluids and germs, and of course keeping everything which is moist inside the skin from leaking out.

However, just as some people have dark skins and some light, and this is genetically determined, some people make better filaggrin glue than others. In fact, with eczema sufferers this filaggrin is more defective or deficient, particularly so in the thin areas of skin simply because the layers of dead cells are also thinner. The CCE or skin envelope in the elbow and knee creases, or at the neck crease, where the skin is more elastic is different; it has to stretch more. Needing to be able to stretch means the skin must have more elastic fibres, and less dense unyielding collagen, another protein below the skin, and thinner dense dead skin cells on the surface. Filaggrin is very important in the stretchy areas of thin skin, to keep the skin moist, hydrated, and intact.

Where proteins such as collagen, or fillagrin are made by living cells, our genes determine the quantity and quality of these protein structures. Where there are other family members, who have also had childhood or adult eczema, it is very likely that there is a genetic tendency. Sometimes the gene expression is not as strong. For example, there may be a gene for muscle development, and in some athletic and sporty people, they have no trouble developing a muscular physique, while other people just don’t have such big muscles. It is just how we are made differently. With skins, some people make skin that is healthy and glowing, managing the sun or irritants without any difficulty, while others don’t.

What has only recently been discovered around three years ago, is that patients with severe atopic eczema are very likely to have a filaggrin gene mutation, the so-called FLG null gene. This means they can manufacture almost no filaggrin, and so the hard dead skin cells don’t bind together properly. People with the most severe FLG null mutations have extremely dry skin that doctors call Icthyosis vulgaris. The skin looks thin and cracked and lizard-like. Where the skin can’t form an impenetrable layer, there is a constant leaking out of fluids, and the skin is not hydrated. Leaking out fluids and also waste products from the skin means there are always irritants in the skin layers which should not be there, and electrolytes in stronger concentration than normal.

Therefore the eczema sufferer itches, having genetically determined dry skin, lacking effective filaggrin. The poor skin barrier is scratched and weakened further by the fingernails, causing inflammation, and breaches in the skin. Sometimes enough to make the skin bleed, and for germs to break through, and start the process of infection with Staph, and flares of eczema. And the Staph releases toxins that make the inflammation worse.

While we don’t yet have artificial filaggrin to apply to the skin, we do have effective emollient creams. These contain a mixture of oils and water that are able to mix and stay mixed – hydrophilic oils. They soften the skin, reduce the loss of fluids and therefore help prevent dryness. Many cosmetic manufacturers try to improve the formula by adding cocoa butter, or vitamin E rich oils. Essentially, the more the oil hardens at room temperature the better, as some of the oil will harden in the dead skin cell layer and form a binding agent.

When children who are susceptible to eczema have daily or twice daily applications of emollient creams to areas that are likely to get eczema, it really does help prevent the skin becoming eczematous. Not only creams help, but also petroleum jelly, or Vaseline, another very effective barrier on the surface keeping the skin moist. You may have a preference for a particular brand or make of emollient cream, and this is often a compromise between easy application, and absorption, and eventual greasiness or staining of fabrics or paper by any residue.

There is a good article written by Dr Sue Lewis-Jones, a consultant dermatologist in Dundee for those who wish to read more about Filaggrin.