Causes and Risk Factors
PsA is an autoimmune condition: the immune system attacks healthy joints, tendons, and skin. Genetics play a strong role — many patients have a family member with psoriasis or PsA — and physical stress on joints and tendons, infections, and obesity may help trigger disease in susceptible people. Having more extensive psoriasis, or psoriasis involving the nails, increases the likelihood of developing arthritis. Unlike some forms of arthritis, PsA is not caused by wear and tear or by an infection of the joint itself, and it cannot be spread from person to person.Symptoms
PsA can look quite different from person to person, and symptoms may flare and settle. Notably, the severity of the skin disease does not predict the severity of the joint disease — mild psoriasis can accompany significant arthritis:- Joint pain, stiffness, and swelling: May affect a few scattered joints on one side of the body or many joints on both sides; morning stiffness lasting more than 30 minutes is typical of inflammation.
- Dactylitis ("sausage digits"): Painful swelling of an entire finger or toe is a hallmark of PsA.
- Enthesitis: Inflammation where tendons attach to bone, classically at the back of the heel or the sole of the foot.
- Nail changes: Pitting, crumbling, or lifting of the nails from the nail bed often accompanies joint disease.
- Back and neck stiffness: Some people develop inflammation of the spine (spondylitis), causing stiffness that improves with movement.
- Eye inflammation: Red, painful, light-sensitive eyes can indicate iritis (anterior uveitis), which needs prompt eye care.
Diagnosis
No single test confirms PsA. Your physician combines the joint examination with the story of your skin and nail disease, blood tests, and imaging. Rheumatoid factor and anti-CCP antibodies are usually negative in PsA, which helps distinguish it from rheumatoid arthritis, and the pattern of involved joints helps separate it from ordinary wear-and-tear osteoarthritis. Blood markers of inflammation, such as the sedimentation rate, may be elevated but can also be normal despite active disease. X-rays or MRI may show characteristic changes at joints and tendon insertions.Treatment
The goal is remission — minimal joint and skin inflammation — and treatment is escalated until that target is reached:- NSAIDs: Ease pain and stiffness in mild joint disease.
- Conventional DMARDs: Methotrexate is commonly used first to control both joint and skin inflammation.
- Biologic agents: TNF inhibitors such as adalimumab and IL-17 inhibitors such as secukinumab and ixekizumab treat skin and joints together and prevent joint damage.
- Targeted oral medicines: Apremilast and JAK inhibitors such as tofacitinib are additional options depending on disease pattern and severity.
- Lifestyle measures: Weight management, regular low-impact exercise, and not smoking improve both symptoms and treatment response.