ADVANCES AND PERSPECTIVES IN PHOTOTHERAPY FOR PSORIASIS

Abstract

Psoriasis is a chronic and inflammatory dermatological pathology affecting approximately 2% of the world population, characterized by a complex pathophysiology involving a cycle of keratinocyte hyperproliferation and immune dysfunction primarily mediated by the IL-23/IL-17 axis. Phototherapy has established itself as an effective therapeutic modality by interrupting this cycle through the controlled interaction of ultraviolet radiation (UVR) with the skin molecular components. Its efficacy is based on multiple mechanisms, including the induction of apoptosis in keratinocytes and T lymphocytes, the reduction of pro-inflammatory cytokines such as IL-12 and IL-23, and the promotion of local immunosuppression. Historically, the treatment evolved from the Goeckerman regimen and the Ingram method to the technological milestone of narrowband UVB (NB-UVB) radiation. This specific radiation has become the modern gold standard due to its superior efficacy and safety compared to broadband UVB. In clinical practice, photochemotherapy (PUVA) combines psoralens with UVA radiation and remains a vital option for severe and resistant cases. The 2024 Brazilian Psoriasis Consensus elevated phototherapy to the same level of importance as methotrexate for the initiation of systemic therapy, targeting ambitious goals such as a 90% reduction in the Psoriasis Area and Severity Index 90. Modern equipment, ranging from professional booths to portable panels and localized units, ensures precise radiation delivery and patient comfort. While biological agents often show higher response rates, phototherapy remains essential due to its high cost-effectiveness, proven safety for pregnant and lactating women, and potential for use in combination therapies to enhance results. Regarding long-term safety, the risk of carcinogenesis is dose-dependent in PUVA, whereas NB-UVB radiation demonstrates a highly favorable safety profile, particularly in individuals with higher phototypes. Thus, phototherapy represents a potent, biologically viable, and accessible solution, with future perspectives pointing toward the integration of controlled home units and targeted lasers to maintain its indispensable role in the therapeutic arsenal against psoriasis.