Psoriasis: The Role of Skin Hydration

Psoriasis is a skin condition characterised by red, scaly patches that cover specific parts of the body. These patches can cause itching and irritation, with the severity varying from one individual to another. They occur as a result of skin inflammation caused by a malfunction of the immune system. T lymphocytes produce inflammatory molecules (cytokines IL-17, IL-22, TNF-alpha, etc.). These molecules stimulate the proliferation of keratinocytes. The renewal period of these cells, normally three weeks, is then reduced to three days. This results in an accumulation of immature keratinocytes on the skin surface, increasing the thickness of the outer layer (hyperkeratosis).

One of the exacerbating factors of psoriasis is skin dryness. Indeed, hydration and the water content of the stratum corneum are key factors enabling the skin to perform its protective barrier function. Numerous studies have shown that the protective barrier function of the skin decreases and that transepidermal water loss increases in psoriatic lesions.

To alleviate the symptoms of psoriasis, it is crucial to maintain a consistent level of skin hydration. The application of moisturising treatments helps to strengthen the protective barrier by maintaining the hydrolipidic film and reducing the risk of skin dehydration . This makes the epidermis more resistant to external aggressions and reduces the Koebner phenomenon. This phenomenon refers to the appearance of new lesions of an already existing dermatosis, in this case psoriasis, on a previously healthy area of skin.

Moisturising products are not a standalone treatment, but they are essential as an adjunctive therapy. In addition to hydrating, these treatments also help soothe the skin from irritations caused by psoriasis.