## 3 Ways to Assess Psoriasis Severity and Therapeutic Strategies for Psoriasis Treatment
### New Therapeutic Approaches in the Treatment of Psoriasis  
#### 3.3.1 Topical Therapy  
Despite the fact that topical agents for the treatment of mild to moderate psoriasis are the mainstay of treatment in these patients, progress in their development has remained limited over the years [35]. Defined as a cytosolic ligand-dependent transcription factor, the aromatic hydrocarbon receptor (AhR) is found in a variety of skin cell types, including (keratinocytes, fibroblasts and melanocytes) and plays an important role in the pathogenesis of psoriasis, and its modulator tapinarof, has become a topical therapeutic agent approved by the FDA in 2022 for the topical treatment of plaque psoriasis in adults [35; 36]. The AhR receptor in healthy skin maintains homeostasis, regulates keratinocyte differentiation, maintains skin barrier function and gene expression [35]. [PERSON], [PERSON], [PERSON], [PERSON], highlighted the role of this receptor in the pathogenesis of psoriasis, in the course of which, within psoriatic plaques, AhR is overactivated and affects the induction of inflammation and the differentiation of keratinocytes and T lymphocytes. Animal studies described in [35] have shown that AhR deficiency leads to increased pro-inflammatory responses and increased production of cytokines such as IL-17 and IL-22, which contributes to the development of psoriasis-like inflammation. Tapinarof, as an AhR agonist, is a promising new therapeutic agent for the treatment of psoriasis [35]. Activation of AhR by tapinarof induces the production of antioxidant enzymes, reducing oxidative stress, and promotes the production of barrier proteins (loricrin, filaggrin), which strengthens the skin barrier [35]. In addition, it also affects the regulation of Th17 and Treg cells, reducing IL-17 expression and inflammation, and additionally exhibits antimicrobial activity, promoting beneficial changes in the skin microbiome and alleviating the course of the disease [35]. The validity of its use was confirmed by a randomized, double-blind Phase III study (PSOARING 1 and PSOARING 2), which evaluated the efficacy of 1% tapinarof cream applied once daily for 12 weeks [35]. The endpoint was PGA (Physician's Global Assessment) response, defined as a score of 0 or 1 and an improvement of \(\geq\)2 degrees from baseline. In both studies, a significantly higher proportion of patients receiving tapinarof (35-40%) achieved a PGA response compared to the placebo group (6.0-6.3%). In addition, Tapinarof showed a favorable safety profile in both the short-term studies (PSOARING 1 and 2) and the long-term open-label study PSOARING 3. Adverse effects occurred in 50.3% (PSOARING 1) and 54.5% (PSOARING 2), respectively, but most were mild to moderate and resolved spontaneously. The most common conditions observed were folliculitis, contact dermatitis, pruritus and headaches. In the PSOARING 3 study, after 52 weeks of treatment, no new adverse reactions were observed. The frequency and severity of skin symptoms did not increase with the duration of therapy, and tolerability of the drug on the skin, including sensitive and flexural areas, was good. There was no accumulation of the drug in the body or increased risk of systemic effects such as cardiac arrhythmias or QT interval prolongation. Tapinarofem 1%-based formulation is an effective and safe agent for the treatment of patients with psoriasis. It is among the alternative therapies in the treatment of psoriasis, enriching the existing group of preparations with proven efficacy in the topical treatment of psoriasis [35].