Key takeaways:
Psoriatic arthritis is an autoimmune condition that affects both the skin and joints.
Symptoms of psoriatic arthritis often start in the hands, feet, and spine.
Getting a diagnosis and starting treatment early gives you the best chance of staying healthy and active.
Psoriatic arthritis is a joint disease (arthritis) that affects about 1 out of 3 people with psoriasis. It’s an autoimmune condition where the body’s own immune system attacks healthy parts of the body.
Early diagnosis and treatment improve outcomes, so it’s important to look out for early signs. That’s especially true if you have psoriasis or another autoimmune disease. Beyond the joints and skin, psoriatic arthritis can affect other parts of the body as well.
In many cases, the first sign of psoriatic arthritis is a skin rash called psoriasis. Rashes may start 5 to 12 years before any joint symptoms develop. Though less common, it’s also possible for joint pain to start first.
There are several different types of psoriasis. Plaque psoriasis is the most common type of psoriasis rash. It often appears on the elbows, knees, and scalp. The rash is made up of thick, raised patches which are pink, red, or violet depending on your skin color. These plaques have a flaky layer of silvery scale over them.
Less common types of psoriasis include:
Inverse psoriasis: smooth, thin patches of skin usually found in skin folds
Guttate psoriasis: small, red or brown round patches, usually on the torso, arms, and legs
Pustular psoriasis: small, pus-filled bumps that look like pimples
Erythrodermic psoriasis: a life-threatening condition where the skin looks “burned”
Psoriatic arthritis can cause pain, swelling, and stiffness in the joints. The official term for this is “inflammatory arthritis.” This is different from osteoarthritis (arthritis caused by wear and tear of aging).
People with psoriatic arthritis describe feeling like their joints are frozen or in need of lubrication. The stiffness of this inflammatory arthritis tends to improve with movement and worsen after long periods of rest. But when psoriatic arthritis is severe, people may feel stiff all day long.
Psoriatic arthritis can affect just about any joint in the body. But it most commonly affects the hands and feet as well as the spine. When arthritis affects the fingers, it can cause dactylitis. When it affects the spine, it’s called spondylitis (more on these below).
Because the nails are an extension of the skin, people with psoriatic arthritis can also notice changes in their nails. Just like in skin psoriasis, there are some distinctive changes that psoriasis can cause in nails:
Nail pitting, tiny dents throughout the nail plate
Onycholysis, when the nail detaches from the nail bed and turns white
Subungual hyperkeratosis, thick scale that forms underneath the tip of the nail
Color changes, small patches on the nail bed that can be yellow-pink, white, or deep red
Lines or ridges across the nails (from top to bottom, or side to side)
Nails that look crumbly
Thickened nails
These changes tend to lessen with treatment — although it can take several months to notice the change.
Psoriatic arthritis can lead to a peculiar enlargement of the fingers and toes. You may hear this kind of swelling called “sausage fingers” or “sausage toes.” The official name is “dactylitis.” One whole finger or toe becomes swollen, red, and painful. This swelling makes it difficult to bend the affected finger or toe.
Psoriatic arthritis may cause inflammation in the spine and pelvis (buttock area), leading to pain and stiffness anywhere from the neck down. The official term for this is spondylitis.
Back pain due to psoriatic arthritis is different from back pain due to osteoarthritis because it’s inflammatory. It’s typically worse in the morning and improves with activity.
Aside from causing inflammation inside the joints, psoriatic arthritis also causes inflammation in the tendons and ligaments around joints. This can cause different types of pain:
Tendonitis: This is when an entire tendon is inflamed. One example of this is Achilles tendonitis, when inflammation in the Achilles tendon causes pain in the back of the leg, right above the heel.
Enthesitis: This is inflammation at the exact spot that the tendon attaches a muscle to the bone. This can cause “tennis elbow.”
Plantar fasciitis: This is when inflammation affects the ligaments that connect your heel to your toes on the sole of the foot, causing foot pain that’s worse in the morning.
Just like psoriatic arthritis can cause inflammation in bones, tendons, and ligaments, it can also cause inflammation of cartilage. One place this happens is in the ribcage, where cartilage connects the ribs to the breastbone. Inflammation here is called costochondritis. Typically, costochondritis pain gets worse when your rib cage expands to take a deep breath in.
People with psoriatic arthritis often feel tired. This makes sense because chronic inflammation can deplete the body’s energy. One study found that over 3 in 4 people with psoriatic arthritis experience fatigue. But it isn’t all bad news. Fatigue can get better with treatment as inflammation lessens.
Psoriatic arthritis can cause different types of inflammation in the eyes, too. Most commonly, it can cause dryness of the eyes or inflammation of the eyelids (blepharitis). Less often, it can cause a severe kind of inflammation called “uveitis” (or iritis). Symptoms of uveitis include sensitivity to light, eye redness, and pain.
Psoriatic arthritis is a “clinical diagnosis.” This means there’s no single test that diagnoses it. The diagnosis is typically made by a rheumatologist (specialist in autoimmune and joint diseases).
Rheumatologists use a combination of clues to get to the bottom of things, including:
Your symptoms
An exam of your body that focuses on your skin and joints
Blood work
Imaging of the joints (like X-rays)
If you have psoriasis, you can take the Psoriasis Epidemiology Screening Tool (PEST) online to identify early symptoms. The PEST can help you figure out if you need to see a rheumatologist.
The journey to diagnosis may not be straightforward because psoriatic arthritis looks different for every person who has it. Your most important job is to report any symptoms right away.
Psoriatic arthritis is an autoimmune disease that affects the skin, joints, and sometimes other parts of the body. In many people, psoriasis rashes start several years before joint symptoms. If you think you could have psoriatic arthritis, reach out to your primary care provider. Early diagnosis and treatment can keep you healthy and active.
Images used with permission from VisualDx (www.visualdx.com).
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Spondylitis Association of America. (n.d.). Could your chronic back pain be caused by spondyloarthritis?