Psoriatic arthritis is suspected when a person with skin or nail psoriasis develops pain and stiffness or swelling in the joints. It’s an autoimmune disease that can affect joints, the end of the tendons, and the spine.

Most people with psoriatic arthritis develop joint pain a few years after a diagnosis of psoriasis, a disease in which patches of skin are inflamed, painful, and itchy. Some patients, however, can develop arthritis initially and psoriasis later. Over time, the inflammation associated with psoriatic arthritis can cause joint damage, leading to impaired range of motion and joint deformity.

Up to 30% of people with psoriasis eventually develop psoriatic arthritis. People often get psoriatic arthritis between the ages of 30 and 50. Psoriatic arthritis affects men and women equally. The condition runs in some families—as many as 40% of people with psoriatic arthritis have immediate family members with psoriasis or psoriatic arthritis.

“There have been tremendous advances in the management of psoriatic arthritis in the last decade, and we are able to effectively treat joint pain and inflammation, as well as prevent long term consequences if the condition is diagnosed and treated early,” says Abhijeet Danve, MD, a Yale Medicine rheumatologist and director of the Yale Spondyloarthritis Program.

Although there is no cure for psoriatic arthritis, treatments can help patients reduce their symptoms, including joint pains and stiffness, skin psoriasis, joint damage, and long-term adverse effects on the organs from uncontrolled inflammation.

Psoriatic arthritis is an autoimmune disease in which people with psoriasis develop inflammation in joints, the ends of the tendons, or the spine. It can involve joints of the hands, feet, wrists, elbows, shoulders, knees, hips, and ankles; the spine and sacroiliac joints (called axial psoriatic arthritis); and ends of tendons (called enthesitis and includes conditions such as plantar fasciitis and tennis elbow). Some patients with psoriatic arthritis develop eye inflammation (iritis or uveitis) and Crohn’s disease or ulcerative colitis.

The degree to which joints are affected in psoriatic arthritis can be variable and not always symmetrical (i.e., occurring on both sides of the body). Joint involvement can be asymmetrical, involve any number of joints, cause “sausage finger,” and involve the spine or tendons. Symptoms of psoriatic arthritis may wax and wane over time, and not every patient develops severe arthritis.

Without treatment, psoriatic arthritis can cause persistent pain and stiffness, limited joint mobility, poor quality of life, and irreversible joint damage. It is also associated with an increased risk of heart disease, strokes, and fatty liver disease.

Treatment not only helps to relieve skin and joint symptoms, but it can also improve the long-term outcomes and minimize organ damage.

Doctors don’t yet know what causes psoriatic arthritis, but certain genes may increase a person’s risk. (The condition runs in some families.) Experts believe that when people have a genetic predisposition for psoriatic arthritis, something—a viral infection, physical trauma, or stress—may trigger the condition.

People with psoriatic arthritis may experience:

• Joint stiffness, pain, and/or tenderness
• Joint warmth
• Joint swelling in a symmetrical or asymmetrical pattern
• A swollen finger or toe
• Back, hip, buttock, or neck pain
• Pain and swelling where a tendon or ligament connects to bone, such as the back of the heel (plantar fasciitis) or elbow (tennis elbow)
• Eye pain, redness, and/or inflammation
• Fatigue
• Joint deformity (over time)

Risk factors for psoriatic arthritis include:

• Having psoriasis
• A family history of psoriasis or psoriatic arthritis
• Inherited mutations of HLA genes or other genetic mutations

Doctors can diagnose psoriatic arthritis after learning about a patient’s medical history and performing a physical exam. There is no specific blood test to confirm the diagnosis of psoriatic arthritis, although doctors may do some tests to check for inflammation and risk factors.

If you believe you have psoriatic arthritis, let the doctor know how long you have experienced symptoms. They will want to know if you had symptoms of psoriasis before you began experiencing joint pain, stiffness, or swelling. They should ask you to describe your joint-related symptoms, including pain, swelling, and/or decreased range of motion. The doctor should ask if your joint pain is symmetrical (on both sides) or asymmetrical (on one side). They’ll also want to know if your symptoms fade and reappear over time.

Doctors will examine your joints for redness, swelling, warmth to the touch, and for signs of deformity, such as fingers or toes that curve instead of remaining straight.

Doctors may offer different diagnostic tests, such as:

• Blood work, to look for inflammation, rule out other conditions, such as rheumatoid arthritis, or check for the presence of HLA gene mutations
• X-rays, which can show whether the joints are damaged and if new bone has formed at the site of any bone destruction
• Other imaging tests, such as ultrasound or magnetic resonance imaging (MRI), which can identify active inflammation, as well as previous damage.
• Aspirating fluid from a swollen joint (typically a large joint such as the knee), to rule out infectious arthritis (when an infection from another part of your body spreads to a joint or the fluid surrounding the joint)

A number of treatments are available for patients with psoriatic arthritis.

Treatments include:

• Non-steroidal anti-inflammatory drugs (NSAIDs), which may ease pain and decrease inflammation in people with mild disease and minimal psoriasis
• Corticosteroid joint injections, which may decrease joint pain and inflammation for the disease (limited to one or two joints)
• Conventional Synthetic Disease-modifying antirheumatic drugs (csDMARDs), such as methotrexate, which help to decrease inflammation in the skin and joints and to slow or stop the joint damage. A few other drugs in this class include sulfasalazine, leflunomide, and cyclosporine.
• Biologic Disease-modifying antirheumatic drugs (bDMARD), a class of drugs that disrupts signals from the immune system, thereby reducing inflammation. Examples include:
  • Tumor necrosis factor inhibitors (TNFi)
  • Interleukin­17 inhibitors
  • Interleukin-23 inhibitors
  • Abatacept

• Oral small molecules such as apremilast and Janus kinase (JAK) inhibitors
• Joint surgery, as needed, if joint destruction from psoriatic arthritis is so severe that joint reconstruction is necessary to improve function and quality of life

Doctors may also recommend the following lifestyle changes:

• Quitting smoking
• Limiting alcohol intake or avoiding alcohol
• Eating a healthy diet rich in fruits, vegetables, and other whole foods, which may lower the risk of diet-related inflammation
• Following a low-impact exercise program, with activities like walking or swimming, to keep the joints in motion
• Weight loss

Treating psoriatic arthritis early may minimize long-term adverse, effects including joint damage or fusion. However, some people may still experience joint pain despite adequate inflammation control and need pain management. In addition, people who take medications for psoriatic arthritis may experience drug-related side effects, including increased risk of infections, allergic reactions, and skin cancers. Some patients may need to switch to alternate medications as some may lose their effectiveness over time.

Psoriatic arthritis also increases a person’s risk of other health conditions—for instance, uncontrolled inflammation may increase the risk of hardening (atherosclerosis) of blood vessels, leading to coronary artery disease or stroke. Psoriatic arthritis is also associated with an increased risk of diabetes, obesity, non-alcoholic fatty liver disease, fibromyalgia, anxiety, and depression.

“The Yale Spondyloarthritis Program was established in 2019 to provide comprehensive care to patients with psoriatic arthritis, a type of spondyloarthritis," says Dr. Danve. "We deliver patient-centered care for psoriatic arthritis by a team of experts that includes dermatologists, gastroenterologists, cardiologists, and physical therapists."