What are the effects of corticosteroid therapy on psoriasis?

In the event of psoriasis, patients witness their immune system reacting abnormally and excessively. The epidermis renews itself rapidly, leading to the appearance of red, scaly patches. For many years, the go-to solution to soothe this inflammatory skin disease has been corticosteroid therapy. This is a treatment carried out with corticosteroids, synthetic molecules that mimic the action of cortisone, a steroid hormone produced by the outer layer of the adrenal glands.

Dermocorticoids are typically used in the treatment of psoriasis. They act on the lesions in three ways.

• An anti-inflammatory effect: Topically applied, dermocorticoids help to soothe the skin by combating inflammation. They inhibit the NF-kB transcription factor by activating the transcription of the IkB gene, thereby conferring anti-inflammatory effects. As a result, they reduce inflammation, swelling, and redness;

• An Immunosuppressive Effect: They reduce the proliferation and migration of T lymphocytes as well as the function of macrophages. Dermocorticoids are also capable of inhibiting the release of cytokines (IL-1 and IL-2). The cytokine IL-1 could potentially modulate the plasticity of T lymphocytes towards the differentiation of Th17 cells, cells involved in the pathology of psoriasis. The cytokine IL-2, on the other hand, is considered a growth factor for T lymphocytes. By regulating the activity of T lymphocytes, dermocorticoids are thus able to modulate the immune response.

• An anti-proliferative effect: Dermocorticoids have an inhibitory effect on the proliferation of skin cells. They are also capable of reducing the synthesis of collagen and proteoglycans by fibroblasts. However, the mode of action of this antiproliferative property is not yet well understood.

Due to their anti-inflammatory, immunosuppressive and antiproliferative actions, dermocorticoids can restore the inflammatory system and inhibit the excessive proliferation of keratinocytes, which leads to the formation of scales. Therefore, dermocorticoids can be useful in treating psoriasis.

The use of dermocorticoids can present certain undesirable effects.

• Skin Atrophy is one of the most common side effects of dermocorticoids. This manifests as a thinning of the skin due to a reduction in some of its components (epidermis, dermis, hypodermis). This observation is explained by their antiproliferative effect on keratinocytes, melanocytes and fibroblasts that synthesise collagen.

• Purpura, ecchymoses, telangiectasias, and permanent erythema are other clinical signs observable after treatment with dermocorticoids. This adverse effect can occur following the stimulation of endothelial cells by dermocorticoids, although its mode of action is not known.

• Other adverse effects have been reported in studies such as hypopigmentation, delayed wound healing, or skin fragility. However, the origin of these effects is not yet very well understood.

Note : Generally, a medical opinion and prescription are required ahead of any use of dermocorticoids.

• LEBRUN-VIGNES B. & al. Dermocorticoïdes. EM Consulte (2011).

• FAURE S. Dermocorticoïdes. Actualités pharmaceutiques (2014).

• ZENKLUSEN C. & al. Actualités pharmaceutiques. Revue Médicale Suisse (2014).