Treatment of Axial Psoriatic Arthritis

Diagnosis and Assessment

The American College of Rheumatology recommends that back pain in patients with psoriasis should be evaluated for possible axial involvement of psoriatic arthritis (PsA) based on the presence of at least two criteria, including inflammatory back pain characteristics, limitation of motion, and radiological criteria 1, 2, 3, 4
Inflammatory back pain characteristics include onset age <45 years, morning stiffness >30 minutes, insidious onset, improvement with exercise, and alternating buttock pain 1, 2, 3, 4
Radiological criteria include plain x-ray showing unilateral sacroiliitis grade 2 or more, syndesmophytes, and MRI changes in sacroiliac joints (bone marrow edema, erosions, joint space narrowing) 2, 3

The European League Against Rheumatism recommends NSAIDs for control of joint symptoms, but not skin symptoms, as first-line therapy for axial PsA 2, 3
Physical therapy and exercise programs are also recommended as first-line therapy for axial PsA 5, 6
TNF inhibitors, such as etanercept or adalimumab, are recommended for patients with moderate to severe axial PsA who fail to respond to NSAIDs and other conventional therapies 2, 3
Disease activity in the spine can be measured using the BASDAI score, where active disease is defined as a score >4, and a treatment response is defined as a BASDAI score <3 or a reduction by 2 points 2

Treatment selection should be based on disease severity, with mild disease treated with NSAIDs and non-pharmacological approaches, moderate disease treated with sacroiliac injections and systemic agents, and severe disease treated with TNF inhibitors 2, 3, 5, 6
Patients should be monitored for response after 6 weeks of treatment, with a treatment response defined as a BASDAI score <3 or a reduction by 2 points 2