How Does Psoriatic Arthritis Affect the Lower Back?

Lower back pain occurs in up to 40% of people with psoriatic arthritis (PsA), as the disease can affect the joints in the vertebrae of the spine or those between the spine and the hips. Psoriatic arthritis in the vertebral joints is called psoriatic spondylitis. When the disease inflames the joints between the spine and the pelvis, it is called sacroiliitis.^1,2

Psoriatic arthritis and lower back pain

When PsA affects the spine, patients often experience back pain and stiffness. Sacroiliitis causes low back pain and may be asymmetrical, affecting only one side of the pelvis. The pain from spondylitis can occur in the lower back, upper back, or neck. Stiffness may be worse in the morning, or after periods of rest. Patients may also experience reduced range of motion.^1,3

How is psoriatic arthritis in the back diagnosed?

Psoriatic arthritis is often diagnosed with the use of imaging techniques, including x-ray and MRI (magnetic resonance imaging). Evidence of inflammation can be seen on x-rays, although MRI is generally the gold standard for imaging spinal disease in psoriatic arthritis. MRI allows visualization of soft tissue as well as bony changes.^1,3

How is psoriatic arthritis in the back treated?

For mild psoriatic arthritis, the pain and stiffness can be alleviated with non-steroidal anti-inflammatory drugs (NSAIDs). In addition, injections of corticosteroids may be used.¹

For moderate to severe disease, treatments that target joint disease in PsA can reduce symptoms and prevent disease progression. Recommended treatments include disease-modifying anti-rheumatic drugs (known as DMARDs). The first step for treatments is usually DMARDs such as methotrexate, leflunomide, or sulfasalazine. Other treatments include medicines that target tumor necrosis factor (TNF), a chemical that produces a wide range of inflammation in PsA. Examples of TNF blockers include etanercept (Enbrel), adalimumab (Humira), infliximab (Remicade), golimumab (Simponi), and certolizumab pegol (Cimzia). Other DMARDs that have proven effective in clinical trials include ustekinumab (Stelara), brodalumab (which is awaiting FDA approval), and secukinumab (Cosentyx). ⁴ The FDA has also recently approved Inflectra (infliximab-dyyb), a biosimilar to infliximab, for the treatment of psoriatic arthritis.⁶

Physical therapy, involving exercises, stretching, heat, cold, and possible vocational readjustments, can be a critical treatment approach to protect the involved joints and maintain function.^1,5