Psoriatic arthritis (PsA) is a chronic inflammatory disease characterized by joint inflammation and skin lesions. Recent research has underscored the critical role of gut microbiota—comprising bacteria, fungi, viruses, and archaea—in the pathogenesis and progression of PsA. This narrative review synthesizes the latest findings on the influence of gut microbiota on PsA, focusing on mechanisms such as immune modulation, microbial dysbiosis, the gut-joint axis, and its impact on treatment. Advances in high-throughput sequencing and metagenomics have revealed distinct microbial profiles associated with PsA. Studies show that individuals with PsA have a unique gut microbiota composition, differing significantly from healthy controls. Alterations in the abundance of specific bacterial taxa, including a decrease in beneficial bacteria and an increase in potentially pathogenic microbes, contribute to systemic inflammation by affecting the intestinal barrier and promoting immune responses. This review explores the impact of various factors on gut microbiota composition, including age, hygiene, comorbidities, and medication use. Additionally, it highlights the role of diet, probiotics, and fecal microbiota transplantation as promising strategies to modulate gut microbiota and alleviate PsA symptoms. The gut-skin-joint axis concept illustrates how gut microbiota influences not only gastrointestinal health but also skin and joint inflammation. Understanding the complex interplay between gut microbiota and PsA could lead to novel, microbiome-based therapeutic approaches. These insights offer hope for improved patient outcomes through targeted manipulation of the gut microbiota, enhancing both diagnosis and treatment strategies for PsA.

Objectives: To develop a practical consensus for standardizing communication between rheumatologists and radiologists regarding magnetic resonance imaging (MRI) of the sacroiliac joints and spine in the diagnosis and management of axial spondyloarthritis (axSpA). Methods: A task force comprising six rheumatologists and five musculoskeletal radiologists with expertise in axSpA imaging reviewed the Assessment of SpondyloArthritis International Society (ASAS) framework to draft initial recommendations and define project goals. A broader expert panel (21 rheumatologists, 19 radiologists) then participated in a voting process to refine and validate these recommendations. Final endorsement was sought from the steering committees of the Italian Society of Medical and Interventional Radiology (SIRM) and the Italian Society of Rheumatology (SIR) using a modified Delphi method. Results: Thirty-one recommendations were validated, organized into eight domains. Domain 1 outlines five overarching principles. Domain 2 comprises recommendations on clinical features, symptoms, and risk factors. Additional domains address MRI technical parameters, including image quality and sequencing (Domain 3), and standardized reporting criteria. For the sacroiliac joints (Domains 4 and 5), five signs of inflammation and six of structural damage are defined. For the spine (Domains 6 and 7), five inflammatory and four structural features are specified. Domain 8 provides guidance on report conclusions. The recommendations were endorsed by SIRM/SIR with 88.5% approval. Conclusion: This consensus offers structured guidance for MRI requesting and reporting in axSpA, fostering clear communication between radiologists and rheumatologists. The standardized approach aims to improve diagnostic accuracy and patient outcomes.