Hyaluronic Acid's Effect on Psoriasis?

A dermatosis still relatively unknown to the general public, psoriasis is characterised by excessive cell renewal and an accumulation of cells in the epidermis, leading to a local inflammation. This disease is often caused by a combination of genetic and environmental factors. Another key element in the pathogenesis of psoriasis is an immune dysfunction. Indeed, people prone to psoriasis have an abnormal number of T lymphocytes in their epidermis, producing inflammation mediators (cytokines IL-17, IL-22, TNF-alpha...). These stimulate the proliferation of keratinocytes, accelerating cell renewal from three weeks to three days. The result is an accumulation of keratinocytes, increasing the thickness of the horny layer: this is referred to as hyperkeratosis.

When suffering from psoriasis, it is crucial to maintain good skin hydration. Dryness is indeed a worsening factor, with several studies showing that the skin's protective barrier function decreases and transepidermal water loss increases in psoriatic lesions. Hyaluronic acid, a natural moisturiser found in the skin, can address this issue. By attracting and retaining water molecules, this hydrophilic sugar limits skin dehydration and contributes to protecting and maintaining the epidermal barrier. However, it should be noted that not all types of hyaluronic acid act in the same way: high molecular weight hyaluronic acid remains on the surface of the stratum corneum and creates a protective film that prevents water from evaporating, while low molecular weight hyaluronic acid penetrates deeper into the epidermis where, in addition to its hydrating effects, it contributes to cellular regeneration and cohesion.

Furthermore, hyaluronic acid possesses intriguing anti-inflammatory properties in the case of psoriasis, which, let us remember, is an inflammatory dermatosis. This active ingredient indeed has a strong affinity for the CD44 receptor, allowing it to inhibit the release of pro-inflammatory cytokines, but also the synthesis of matrix metalloproteinases (MMP) and prostaglandin E2 (PGE2), inflammatory molecules that contribute to exacerbating psoriatic lesions. Studies in vitro conducted with human keratinocytes have also shown that cells treated with hyaluronic acid produced less interleukin-8 and tumour necrosis factor (TNF-α), other agents of inflammation.

Finally, there is a clinical trial conducted today with 10 patients suffering from psoriatic lesions, which has focused on the effects of hyaluronic acid on this condition. These individuals applied for one week patches of 26 x 26 mm with hyaluronic acid micro-needles. This non-invasive and painless technology enhances the delivery of hyaluronic acid and improves its penetration. Indeed, the micro-needle patches facilitate the absorption of active ingredients by the skin by creating numerous micro-channels in the horny layer. After one week, a complete resolution of the lesions was observed in two patients. Eight out of ten people considered themselves "satisfied" or "very satisfied" with the results. It is also worth noting that no adverse effects were observed.

Key Takeaway : Even though more studies are needed, there are promising evidences regarding the effect of hyaluronic acid on psoriasis. However, this active ingredient cannot replace a dermatological treatment.