Dry Skin

A large portion of the population, especially children younger than 10 and people over 60, suffer from dry skin. Between the ages of 10 and 60, more women than men have this condition. Caused by a deficit in the natural moisturising factor Urea, dry skin varies in severity from problem to extreme.

(Problem) Dry Skin
Characterized by mild scaling, roughness, tightness and possibly itching, problem dry skin results from a reduced water-binding capacity due to the lower concentration of natural moisturising factors. These include urea and amino acids, as well epidermal lipids (particularly triglycerides, free fatty acids, and cholesterol).

The breakdown of particular amino acids, mostly arginine, in the cell cornification process leads to the formation of urea. A deficiency of amino acids results in a reduction in the urea concentration within the skin. The lack of moisturising factors leads to an increase in water loss and skin dehydration. Applying a moisturiser with 5% urea can compensate for this loss and return skin to normal.

Extremely Dry Skin
Mostly seen with older people, as well as on the hands, extremely dry skin is characterised by roughness, chapping, callus formation, scaling and frequent itching. Extremely dry skin requires a greater concentration of urea (often 10% or higher).

Atopic, dry and reddened Skin
Roughly 15 - 20% of the population suffers from atopic dry skin predisposing them to neurodermatitis which results in:

• Scaling, thickening and cracking
• Intensive itching
• Tendency to reddening and inflammation (atopic eczema)

Not only moisture deficiency causes this, but also a disruption of fatty acid metabolism, which leads to a breakdown of the barrier function.

Normal	Dry	Atopic Eczema

Optical microscope images
1. Horny layer
2. Epidermis (uppermost skin layer)
3. Dermis/papillae

Causes and treatment of atopic dry skin conditions
In people with atopic dry skin, despite a sufficient intake of the essential omega-(n)-6 fatty acid, the concentration of linoleic acid and its metabolites such as gamma linolenic acid is markedly reduced in the epidermis. At the same time, there is an excess of the monounsaturated omega-9 fatty acids, especially oleic acid. This leads to increased formation of dysfunctional ceramides esterified with oleic acid in atopic dermatitis rather than the physiological ceramides that are especially rich in linoleic acid.

This deficiency has wide-ranging consequences for the skin condition of the neurodermatitis sufferer. Systemical and topical application of omega-6 fatty acids can thus have a beneficial effect.

In addition to oral substitution, the application of omega-6 fatty acid-containing skincare products has proved effective, as they contain a high proportion of linoleic acid and gamma linolenic acid and can be applied directly to the skin. Especially in children, the combination of oral and topical application of essential fatty acids in the form of evening primrose oil is a proven and very safe treatment concept (the "sandwich" therapy).

Evening primrose oil, rich in highly beneficial linoleic and gamma linolenic acid, applied both orally and topically has been clinically proven effective.

Ceramides: the most important barrier-forming lipids
When there is a deficiency of long-chained essential fatty acids - especially linoleic acid and gamma linolenic acid - a change in the ceramides follows: This group of substances forms what is known as the lipid barrier between the horny cells - similar to the mortar between the bricks of a wall - which plays a central role in the regulation of moisture in the skin. Thus the stability and functionality of the permeability barrier is dependent on a sufficient supply of essential fatty acids.

Scientific tests have shown that locally applied omega-6 fatty acids are absorbed directly into the linoleic acid-dependent lipid structure and thus restore the diminished barrier function in the atopic patient.