By Cheah Ui-Hoon

A NEW understanding of a cause of common skin problems has emerged - the skin itself is to blame.

'Recently we discovered the skin has a lot of proteins that protect it,' says Professor Alain Taieb, head of the department of dermatology and paediatric dermatology at the prestigious Bordeaux University Hospital in France.

'We have moved on from the idea that atopic dermatitis was caused by some internal disturbance, to realise now that it is a skin disorder. That is very important for us in dermatology and skincare - to consider the skin itself as a target for the prevention of atopic dermatitis.'

Doctors used to think the skin was the target of the disease and not the cause. Now that they understand that the disease originates in the skin, this has implications for regular skincare regimens, says Prof Taieb. 'We are putting more emphasis on treating the barrier itself.'

One protein that protects the skin is filiggrin. Its loss causes permeability, so irritants and allergens get through easier.

The lack of filiggrin is now known as one of the main causes of common atopic dermatitis - inflamed, itchy skin. 'And for infants, many of whom have atopic dermatitis in the first few months of their life, it's a very disturbing condition to have,' says Prof Taieb, who specialises in infant atopic dermatitis.

Filiggrin is a key protein on the uppermost layer of the skin and provides natural moisturising factors. 'This helps maintain good impermeability and barriers in skin,' he says. The lack of filiggrin is a genetic defect in about 30-50 per cent of patients.

This also applies to adults, as most cases of atopic dermatitis stem from infancy. 'We find that most of them have dry skin and lines on their palms, and their skin is also rougher,' says Prof Taieb. 'These are markers for filiggrin deficiency.'

The lack of filiggrin is also a sign of asthma, which atopic dermatitis sufferers commonly suffer. 'When the skin barrier is bad it will enhance the entry of irritants and allergens like house mites,' the professor says.

The skin barrier is inherited, but it's not just one gene that causes the disease - and the environment is also important, he adds. 'Different kinds of environments can cause the disease. Hot and dry weather in the West is a major concern for triggering attacks of atopic dermatitis, while in Asia, air-conditioning and wet weather are also triggers.'

Prof Taieb points out that maintaining good skin pH is very important. 'The skin is slightly acidic, at 5 to 6 pH, and when you increase the alkaline, it increases the breakdown of the barriers.'

Scientists have known this for some time, but they understand it better now, he says. 'Being in an alkaline state increases the efficiency of skin proteasis - enzymes that break down the proteins which are important for the skin barrier.'

So when using skincare emollients or cleansers, take care not to use those that increase the skin's pH. Soap is high alkaline, for example. Prof Taieb says companies like Galderma were clearly on to something when they developed pH-correct cleaners, but the implications are better understood now.

Going back to infant atopic dermatitis, he points out that children generally grow out of it around the age of three and upwards. 'Because we think the skin itself can improve and its function mature over time,' he says.

But people who suffer atopic dermatitis during infancy may not grow completely out of it - there can be flare-ups in adulthood because they have a mis-regulated immune system that reacts to common proteins in food and the environment.

Treatment is now centred on the skin itself, treating super-infection and inflammation such as by using tacrolimus ointment, which has been in the market for five to 10 years.

'A good skincare regimen and low-irritancy cleansers and moisturisers are also key for prevention,' says Prof Taieb. 'Moderate exposure to the sun is also good for building up the skin barrier.'

This story was first published in The Business Times.