Psoriatic arthritis risk factors: who is more likely to get it and why

What psoriatic arthritis is

Psoriatic arthritis is a progressive inflammatory condition of the joints and of the entheses, the places where tendons and ligaments attach to bones. It happens when the immune system, for unknown reasons, becomes overactive and creates inflammation, leading to pain and swelling (NIAMS).

MedlinePlus says some people with psoriasis have psoriatic arthritis. It is often mild but can sometimes be serious and affect many joints, and the joint and skin problems do not always happen at the same time (MedlinePlus).

There is no score or calculator on this page; the factors below are the ones NIAMS names.

Who is more likely to get psoriatic arthritis

Anyone can get it, but it is most common in adults and affects men and women equally (NIAMS). NIAMS names these factors (NIAMS):

• Having psoriasis. The large majority of people who get psoriatic arthritis already have psoriasis. On average, the arthritis develops about 7 to 10 years after the skin symptoms begin, though a small group have joint pain before the skin rash.
• Severe psoriasis. Among people with psoriasis, having severe psoriasis appears to be associated with a higher risk of arthritis.
• Obesity. Obesity also appears to be associated with a higher risk among people with psoriasis (see obesity risk factors).
• Family history and genes. Many people who get psoriatic arthritis have a family history of the disease, and researchers have identified some of the genes involved.

It is not yet clear who will develop psoriatic arthritis (NIAMS).

What may trigger it

Psoriatic arthritis is an immune-mediated disease. Scientists do not fully understand why the immune changes happen, but certain factors may trigger the immune system. Environmental factors such as obesity, infection, injury or stress may trigger the onset, and sometimes stressful events, trauma to the joints or bones, or infections may trigger the disease (NIAMS).

Symptoms

Symptoms vary greatly from person to person and may include (NIAMS):

• Scaly, inflamed patches of skin typical of psoriasis, often on the scalp, elbows or knees.
• Stiffness, pain and swelling of one or more joints, including the spine (neck, lower back and hips); stiffness is often worse in the morning or after resting.
• Fatigue or a lack of energy.
• Tenderness where tendons or ligaments attach to bones, commonly the back of the heel and the sole of the foot.
• Painful, sausage-like swelling of a whole finger or toe.
• Nail changes, such as pitting (tiny dents), crumbling or nails separating from the nail bed.
• Eye inflammation, especially uveitis, which can cause eye pain, redness and blurry vision and must be treated promptly to avoid vision loss.
• Inflammatory bowel disease, in some people (see Crohn's disease risk factors).

See your doctor soon if joint symptoms arise, because early treatment is associated with better outcomes and less damage from the disease (NIAMS).

Diagnosis

There is no definitive test. A doctor may ask about a family history of psoriasis or psoriatic arthritis, examine your joints, skin and nails (swollen and tender joints, psoriasis skin lesions and nail changes are significant signs), take a blood sample to check for other conditions such as rheumatoid arthritis, and order imaging such as x-rays, ultrasound or MRI (NIAMS). MedlinePlus also names a physical exam and imaging tests (MedlinePlus).

Treatment and living with psoriatic arthritis

There is no cure, but treatments can slow its progression, lessen pain and protect the joints (NIAMS). Milder disease may be treated with over-the-counter anti-inflammatory and pain medicines or corticosteroid injections into affected joints; more persistent or severe disease may be treated with disease-modifying anti-rheumatic drugs (DMARDs), biologic therapies or oral targeted therapies (NIAMS). In rare cases, surgery may be needed to repair or replace damaged joints (MedlinePlus).

NIAMS suggests working with your doctor on a plan to quit if you smoke (some studies have shown that the more a person smokes, the worse the symptoms tend to be), reaching and keeping a healthy weight, trying low-impact exercise such as walking, cycling, swimming, yoga or tai chi after talking with your doctor, protecting your joints, and getting support for the emotional and mental effects (NIAMS).

Common questions

Can you get psoriatic arthritis without psoriasis?

Most people who develop it already have psoriasis when they are diagnosed, but a small group have joint pain before the skin rash (NIAMS).

Is psoriatic arthritis genetic?

Genes play a role: many people who get it have a family history of the disease, and researchers have identified some of the genes involved (NIAMS).

How long after psoriasis does psoriatic arthritis start?

On average, about 7 to 10 years after the skin symptoms begin (NIAMS).