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.
Living With Psoriatic Arthritis
Psoriatic arthritis is now a condition most people control rather than endure, but only when treatment is adjusted until inflammation is gone rather than merely reduced, and when what travels with it, from weight to eye disease to sun exposure, is handled alongside the joints.
Treat to target, and do not settle for better
Methotrexate is taken once a week, never daily, with folic acid on the other days, and blood tests for the liver and blood count are repeated regularly; alcohol is kept minimal because the two together strain the liver. If joints are still swollen after three to six months, treatment is escalated rather than continued, because damage accumulates at levels of inflammation that do not hurt much. The inflammatory arthritis page covers the monitoring rules shared across the group.
Choosing a biologic by what else you have
IL-17 inhibitors such as secukinumab and ixekizumab clear skin exceptionally well but are avoided in anyone with inflammatory bowel disease, which they can worsen. TNF inhibitors such as adalimumab are preferred when uveitis or bowel disease is also present. IL-23 inhibitors such as guselkumab and risankizumab are well tolerated and dosed infrequently. Apremilast suits milder disease and needs no blood monitoring. JAK inhibitors such as tofacitinib and upadacitinib carry a warning about heart events and cancer in people over fifty with cardiovascular risk factors. Before any of them, tuberculosis and hepatitis B are screened and vaccines including shingles are brought current.
Tendons, digits, and the spine need more than NSAIDs
Naproxen or celecoxib eases pain and stiffness but does not prevent damage. Enthesitis at the heel and dactylitis of a whole finger respond poorly to methotrexate and better to biologics, and back stiffness that improves with movement means spinal involvement, which is treated the way ankylosing spondylitis is, with a biologic rather than a conventional drug.
The conditions that travel with it
Obesity and metabolic syndrome are common, and excess weight measurably reduces the response to biologics, so weight loss is part of treatment rather than a side project. Cardiovascular risk is raised, and blood pressure and cholesterol are treated more aggressively than the numbers alone would suggest. Uric acid runs high in psoriasis, so a single hot swollen toe may be gout rather than a flare and is checked before treatment is escalated. A red, painful, light-sensitive eye is iritis until proven otherwise and needs same-day eye care.
Sun, humidity, and the skin
Sunlight improves psoriasis plaques, but methotrexate and several other drugs increase sun sensitivity, and a sunburn can trigger new plaques where the skin was injured, so exposure is short and protected. Many patients notice more joint pain with the humidity and pressure swings here, which our arthritis and humidity guide addresses. Our musculoskeletal team coordinates monitoring between rheumatology and dermatology visits. The NIAMS, the American College of Rheumatology, and the National Psoriasis Foundation publish patient guidance on treatment and daily life.
If your psoriatic arthritis is better but joints are still swollen, or you have not had a treatment review in the past six months, schedule a visit.