Psoriatic arthritis (PsA) is a condition that combines the swollen, sore joints of arthritis with the skin disease psoriasis. Psoriasis causes itchy, scaly red patches to appear on the skin and scalp.
Types of psoriatic arthritis
There are five types of PsA:
Symmetric PsA affects the same joints on both sides of the body. For example, both the left and right knees. Symptoms can be like those of rheumatoid arthritis (RA). But symmetric PsA tends to be milder and cause less joint deformity than RA. However, symmetric PsA can be disabling. About 50 percent of people with PsA have this type.
Asymmetric PsA affects a joint or joints on one side of the body. Your joints may feel sore and turn red. Asymmetric PsA is generally mild. It affects about 35 percent of people with PsA.
Distal interphalangeal predominant (DIP) PsA involves the joints closest to the nails. These are known as the distal joints. It occurs in about 10 percent of people with PsA.
Spondylitis PsA involves the spine. The entire spine from the neck to the lower back may be affected. This can make movement very painful. The hands, feet, legs, arms, and hips may also be affected.
Arthritis mutilans is a severe, deforming type of PsA. About 5 percent of people with PsA have this type. Arthritis mutilans usually affects the hands and feet. It can also cause pain in the neck and lower back.
What are the symptoms of psoriatic arthritis?
Symptoms of PsA are different for each person, and they can be mild to severe. Sometimes your condition will go into remission and you’ll feel better for a while. At other times your symptoms may get worse. Your symptoms also depend on the type of PsA you have.
General symptoms of PsA include:
- swollen, tender joints on one or both sides of the body
- morning stiffness
- fingers and toes that swell up like sausages
- painful muscles and tendons
- scaly skin patches, which may get worse when joint pain flares up
- nail pitting
- separation of the nail from the nail bed
- eye redness (conjunctivitis)
- eye pain (uveitis)
Spondylitis PsA, in particular, can also cause the following symptoms:
- pain and stiffness in the spine
- pain and swelling in the hips, knees, ankles, feet, hands, wrists, and other joints
- swollen toes or fingers
Symmetric PsA affects five or more joints on both sides of the body. Asymmetric PsA affects less than five joints, but they can be on opposite sides of the body. For example, the right wrist and left knee.
Arthritis mutilans deforms the joints. It can shorten the affected fingers and toes. Distal PsA causes pain and swelling in the end joints of the fingers and toes.
What causes psoriatic arthritis?
In PsA, your immune system attacks your joints and skin. Doctors don’t know for sure what causes these attacks. They think it stems from a combination of genes and environmental factors.
PsA runs in families. About 40 percent of people with the condition have one or more relatives with PsA. People inherit a tendency to get PsA. Then, something in their environment triggers the disease. That trigger could be a virus, extreme stress, or an injury.
Risk factors for psoriatic arthritis
You’re more likely to get PsA if you:
- have psoriasis
- have a parent, brother, or sister with PsA
- are between the ages of 30 and 50, although children can get it, too
- have had strep throat
- have HIV
PsA puts you at risk for complications that include:
Diagnosing psoriatic arthritis
To diagnose PsA, your doctor has to rule out other causes of arthritis, such as RA and gout, with imaging and blood tests.
These imaging tests look for damage to joints and other tissues:
- X-rays check for inflammation and damage to bones and joints. This damage is different in PsA than it is in other types of arthritis.
- MRI uses radio waves and strong magnets to make images of the inside of your body. These images can help your doctor check for joint, tendon, and/or ligament damage.
Blood tests for these substances help assess any inflammation present in your body:
- C-reactive protein is a substance your liver produces when there is inflammation in your body.
- Rheumatoid factor (RF) is an auto-antibody produced by your immune system. It’s usually present in RA, but negative in PsA. An RF blood test can help your doctor tell whether you have PsA or RA.
- Joint fluid test removes a small amount of liquid from your knee or other joint. If uric acid crystals are in the fluid, you might have gout instead of PsA.
How is psoriatic arthritis treated?
The goal of PsA treatment is to improve symptoms like skin rash and joint inflammation. You have many different treatment options. A typical treatment plan will include one or more of the following:
Nonsteroidal anti-inflammatory drugs (NSAIDs)
These medications help control joint pain and swelling. Over-the-counter (OTC) options include ibuprofen (Advil) and naproxen (Aleve). If OTC options aren’t having an effect, your doctor may prescribe NSAIDs in higher doses.
When used incorrectly, NSAIDs can cause:
- stomach irritation
- stomach bleeding
- heart attack
- liver and kidney damage
Disease-modifying antirheumatic drugs (DMARDs)
These medications prevent joint damage to slow the progression of PsA. You get these medicines by injection or infusion.
The most commonly prescribed DMARDs include:
Apremilast (Otezla) is a newer DMARD. It works by blocking phosphodiesterase 4, an enzyme involved in inflammation.
DMARD side effects include:
- liver damage
- bone marrow suppression
- lung infections
Biologic drugs, also known as TNF-alpha inhibitors, block the effects of the protein tumor necrosis factor-alpha. This reduces inflammation and improves symptoms like stiff and swollen joints.
You receive biologics through an injection under your skin or as an infusion. Because these medicines dampen the immune response, they can increase your risk for serious infections. Other side effects include nausea and diarrhea.
Because biologics are expensive, your doctor may not try one of these medicines unless your condition hasn’t improved with other treatments.
Commonly prescribed biologic drugs include:
These medications can bring down inflammation in your body. For PsA, they’re usually injected into the affected joints. Side effects include pain and a slight risk of joint infection.
Medications like azathioprine (Imuran) and cyclosporine (Gengraf) calm the overactive immune response in PsA. They’re not used as often now that TNF-alpha inhibitors are available. Because they weaken the immune response, immunosuppressants can increase your risk for infections.
Creams, gels, lotions, and ointments can relieve the itchy PsA rash. These treatments are available over the counter, and with a prescription.
- calcitriol or calcipotriene, which are forms of vitamin D-3
- salicylic acid
- steroid creams
- tazarotene, which is a derivative of vitamin A
Light therapy and other PsA medicines
Light therapy uses medicine, followed by exposure to bright light, to treat psoriasis skin rashes.
A few other medicines also treat the symptoms of PsA. These include secukinumab (Cosentyx) and ustekinumab (Stelara). These drugs are injected under the skin. They can increase your risk of infections and cancer.
Can lifestyle changes help ease psoriatic arthritis symptoms?
There are things you can do at home to help improve your symptoms:
Make a few changes to your diet. Eat more fresh fruits and vegetables, which help lower inflammation and control your weight. Excess weight puts more pressure on already sore joints. Limit sugar and fat, which are pro-inflammatory.
Add exercise to your daily routine. Keeping your joints moving can ease stiffness. Being active for at least 30 minutes a day will also help you lose excess weight, as well as give you more energy. Ask your doctor what type of exercise is safest for your joints. Biking, walking, swimming, and other water exercises are gentler on the joints than high-impact exercises like running or playing tennis.
Break bad habits. Smoking is bad for your joints — as well as the rest of your body. Ask your doctor about nicotine replacement, medicine, and counseling to help you quit. Also limit alcohol, which can interact with some PsA medications.
Relieve stress. Tension and stress can make arthritis flares even worse. Meditate, practice yoga, or try other stress-relief techniques to calm your mind and body.
Use hot and cold packs. Warm compresses and hot packs can ease muscle soreness. Cold packs can also reduce pain in your joints.
Move in ways that protect your joints. Open doors with your body instead of your fingers. Lift heavy objects with both hands. Use jar openers to twist open jar lids.
What can trigger a psoriatic arthritis flare-up?
Certain things can set off PsA flares. Everyone’s triggers are different. To learn your triggers, keep a symptom diary. Each day, write down your symptoms, and what you were doing when they started. Also note whether you changed anything in your routine — for example, if you started taking a new medicine.
Common PsA triggers include:
- infections like strep throat
- injuries such as a cut, scrape, or sunburn
- cold weather
- heavy drinking
- medicines such as lithium, beta-blockers, and antimalarial drugs
Although you can’t avoid all of these triggers, you can try to manage stress, stop smoking, and cut down on drinking.
Ask your doctor if you take any of the medicines known to set off PsA symptoms. If so, you might want to switch to a new drug.
Everyone’s outlook is different. Some people have very mild symptoms that only cause problems from time to time. Others have more severe and debilitating symptoms. The more severe your symptoms are, the more PsA will affect your ability to get around. People with a lot of joint damage may find it hard to walk, climb stairs, and do other daily activities.
Your outlook will be affected if:
- You were diagnosed with PsA at a young age.
- Your condition was severe when you were diagnosed.
- A lot of your skin is covered in rashes.
- A few people in your family have PsA.
To improve your outlook, follow the treatment regimen your doctor prescribed. You might have to try more than one drug to find what works best for you.