Unravelling Fibromyalgia in Psoriatic Arthritis

Fibromyalgia is a common condition causing widespread pain, fatigue, sleep disturbance, and cognitive dysfunction. It frequently coexists with chronic rheumatic diseases, including psoriatic arthritis (PsA), complicating diagnosis and management. This narrative review explores the interaction between fibromyalgia and PsA, highlighting recent studies that demonstrate that between 18% and 64% of patients with PsA have fibromyalgia with significant impact on disease assessment and quality of life. Patients with fibromyalgia have markedly higher scores for pain, tenderness, fatigue, poor sleep, and standard PsA disease activity measures. Where this overlap occurs "disease activity" indices often reflect fibromyalgia symptoms rather than true inflammation, leading to potential overtreatment with disease-modifying drugs rather than appropriate pain-modulating or lifestyle interventions. Additionally, fibromyalgia symptoms exist along a continuum, with many patients showing subthreshold manifestations that still affect function and well-being. Tools such as the Fibromyalgia Impact Questionnaire and Polysymptomatic Distress Scale help distinguish the central sensitization symptoms that characterize fibromyalgia from inflammatory activity and damage in joints and tendon sheaths that characterize PsA. Both peripheral and central pain-related neural mechanisms, including comorbid factors such as obesity and disease burden, contribute to fibromyalgia in PsA. Activation of the stress response likely contributes significantly to fibromyalgia in this setting. Fibromyalgia itself is seen not simply as a comorbidity but as part of the body's neurobiological stress response to chronic illness. Recognizing fibromyalgia within PsA is crucial to tailor management, improve outcomes, and avoid unnecessary treatments. This complex clinical picture requires nuanced management beyond that of inflammation alone.