What causes psoriatic arthritis?
In this article, we discuss what medical experts currently understand about the causes, potential triggers, and risk factors of PsA.
When the immune system attacks healthy joint tissue, it can cause symptoms, such as pain.
Medical professionals do not yet fully understand the causes of psoriasis.
However, they do know that the immune system has an active involvement in psoriatic conditions. The immune cells attack healthy joint tissue, causing inflammation, swelling, and pain.
Genetics may play a role in PsA. Psoriatic conditions tend to run in families. In fact, over 40% of people with PsA have a family member with the condition.
Some people without the characteristic skin involvement of psoriasis may still develop PsA.
Environmental factors may also play a role. Injury, infection, and exposure to environmental triggers can cause PsA to flare, especially in people with a family history of the condition.
The period of time during which symptoms get worse is called a flare. Flares often have a specific environmental trigger.
Common triggers include:
- exposure to cigarette smoke
- infections or skin wounds
- severe stress
- cold weather
- drinking too much alcohol
- taking certain medications
Quitting smoking can help reduce the risk of psoriasis flares. Although data are not yet available to confirm the exact effects of smoking on PsA, the National Psoriasis Foundation suggest that it might reduce the impact of treatment.
Understanding the potential triggers of PsA flares increases the chance of being able to prevent them. Keeping a journal may help a person identify and avoid their triggers.
Sharing this information with a doctor can help a person identify effective treatments or simple lifestyle changes that could improve symptoms.
Psoriasis is a risk factor for PsA.
Several risk factors are linked to PsA:
- Medical history: Having psoriasis is a key risk factor for PsA. In most cases, people develop PsA after developing the skin symptoms of psoriasis. However, it is also possible for PsA to develop before any skin lesions occur, making an accurate diagnosis difficult to establish.
- Age: People between the ages of 30–50 years are most likely to develop PsA. However, it can set in at any age.
- Family history: People with a family history of psoriasis or PsA are more likely to develop the conditions than those without.
Types and symptoms
There are several types of PsA, including psoriatic spondylosis (which affects the spinal column), enthesitis (which tends to affect the feet, pelvis, and ribs), and dactylitis (which affects the fingers and toes).
Doctors also categorize PsA by the number of joints it affects. For example, oligoarticular PsA affects up to four joints. Polyarticular PsA is more debilitating, leading to pain and inflammation in more than four joints.
PsA can affect the peripheral joints, including the elbows and wrists. Symptoms can also develop in the axial skeleton, which includes the shoulders and hips.
Symptoms can range in severity from mild, occasional flares to constant pain and severe joint damage. Some common symptoms include:
- eye redness
- joint stiffness
- reduced range of motion
- painful and swollen joints that are warm to the touch
Diagnosis and treatment
Imaging scans can help a doctor confirm a PsA diagnosis.
To diagnose PsA, a doctor may:
- take a detailed medical history
- perform a thorough physical exam
- order X-rays, MRI scans, and ultrasound scans to check for damage and examine joints in more detail
- perform a rheumatoid factor and anti-cyclic citrullinated peptide test, which can help rule out rheumatoid arthritis
- test for the presence of uric acid crystals in joint fluid, if there is concern about gout
Anyone with a history of psoriasis and joint pain should seek medical attention and mention that they have psoriasis to support an accurate diagnosis.
Doctors primarily use biologics to treat moderate to severe PsA. Biologics target specific parts of the immune system and help reduce the regularity and severity of flares.
Several different medications are effective against the symptoms of PsA. The doctor will prescribe a medication based on levels of pain, swelling, and stiffness.
- TNF-alpha inhibitors (TNFIs): These drugs block the production of a protein that contributes to inflammation and swelling. They also help reduce pain.
- Nonsteroidal anti-inflammatory drugs: These can be very effective for mild pain and inflammation. Examples include ibuprofen or naproxen. Many are available over the counter.
- Osmotic release drugs: These are helpful for people who cannot take TNFIs, including those with congestive heart failure, recurrent or severe infections, or another demyelinating or autoimmune condition. Examples include tofacitinib (Xeljanz) and Apremilast (Otezla).
- Disease-modifying antirheumatic drugs (DMARDs): These help slow the joint damage associated with PsA. One example is methotrexate. However, a doctor will only prescribe methotrexate if other PsA treatments have not been successful.
Some of these drugs can have serious side effects, so people with PsA should adjust their treatment plan if adverse effects become severe.
Cost is also an important consideration. Insurance companies have varying levels of coverage for different medications. A person should speak to their coverage provider about the available options.
People with PsA may also benefit from the following physical and lifestyle interventions:
- physical therapy
- occupational therapy
- weight control
- a light exercise regimen that includes yoga, tai chi, or swimming
The exact causes of PsA are not yet clear. However, many scientists and medical professionals believe that it develops due to a faulty reaction in the immune system.
Although genetics appear to play a role in its development, certain environmental triggers can also give rise to PsA, including exposure to smoke, stress, and cold weather. Risk factors for PsA include age and family history.
Many treatment options are available for PsA, so a person who begins to experience symptoms should seek prompt medical attention.
Which exercises are safe for people with PsA?
Most types of exercise will be safe if people gradually increase the duration and intensity. They should pay attention to any signs of pain or discomfort, then adjust the exercise routine.
In general, lower-impact exercise such as tai chi and yoga are good options to start with. If accessible, swimming or doing other water exercises in a warm pool are excellent choices for people with PsA.
Scheduling an initial meeting with a physical or occupational therapist may help a person develop a safe, individualized plan. Working with a personal trainer who has knowledge of chronic illnesses and arthritis is an additional option.Nancy Carteron, MD, FACR Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.