If you have psoriatic arthritis (PsA), chances are that you feel its effects in swollen or stiff fingers or toes. PsA commonly involves the small joints closest to the tips of the fingers and toes, called the distal interphalangeal (DIP) joints. More than half of people with PsA have DIP joint involvement.
PsA that affects the DIP joints is known as distal interphalangeal-predominant PsA, one of the five types of PsA. The other types are spondylitis, symmetrical polyarthritis, asymmetrical oligoarthritis, and arthritis mutilans.
This article provides an overview of DIP psoriatic arthritis.
The DIP joint is the joint closest to the tip of your finger or toe, just below the nail.
For most people, PsA typically begins in four or fewer joints, known as oligoarticular PsA, but it can advance and affect five or more joints, which is called polyarticular PsA. When more than half of the joints affected by PsA are DIP joints, the condition is known as DIP-predominant PsA. Most people diagnosed with PsA also have skin lesions associated with psoriasis.
DIP-predominant PsA can affect one side of the body (asymmetric PsA) or both sides (symmetric PsA). Symptoms may be similar to those of other types of PsA, such as:
Radiographic changes are changes that can be seen using imaging tests, such as X-ray, MRI, and ultrasound.
Joint damage from PsA happens when inflammation destroys the bones and tendons in the joint and new bone growth occurs inappropriately. By using an imaging test such as an X-ray, your doctor can look for changes to the bones in your hands, such as:
An MRI can reveal problems with the tendons and ligaments in your hands and feet.
DIP-predominant PsA can cause joint pain and impair hand function by decreasing your range of motion, grip strength, and fine motor skills. One study from the journal ACR Open Rheumatology found that hand dysfunction in PsA was similar to that of rheumatoid arthritis (RA).
MyPsoriasisTeam members have described how having less hand function has affected their lives. One member shared, “My fingers hurt and are swollen. One finger is crooked. I cannot make a fist with that hand.”
Another member commented on how PsA in their hands makes it hard for them to complete daily tasks: “My hands are to the point where I can only use them to do things like eat or brush my teeth. I can’t open bottles or cans, open my medications, hold a spatula longer than a few seconds at a time, twist a lot of doorknobs, or drive farther than just a few miles.”
The most important risk factor for developing DIP PsA is being diagnosed with psoriasis. About one-third of people with psoriasis develop PsA. Of those who have PsA, about 10 percent have DIP-predominant arthritis. Some types of psoriasis are associated with an increased risk of PsA, including:
PsA is most commonly diagnosed in people between the ages of 30 and 50. Men and women are equally affected by PsA, according to Cleveland Clinic. You may be at increased risk if you have a family member with PsA. About 40 percent of people with the condition have a family history of PsA.
Your doctor will diagnose DIP PsA based on your symptoms, a physical exam, and imaging tests such as X-rays or MRI.
There isn’t a definitive way to diagnose PsA using a laboratory test. However, your doctor may run tests to rule out other diseases, such as:
Your doctor may look for signs and symptoms of DIP-predominant PsA that distinguish it from other conditions. For example, people with DIP-predominant PsA often have different symptoms on either side of their body and may also have nail symptoms. Additionally, DIP joint involvement is common in PsA and inflammatory osteoarthritis but not in gout and RA.
A laboratory test called rheumatoid factor (RF) can help distinguish PsA from RA. RF is an antibody commonly found in the blood of people with RA but not in those with PsA. A negative RF test result can rule out RA but does not mean you have PsA.
It’s important to diagnose PsA early so you can get prompt treatment — a delay in diagnosis of just six months can increase your risk of joint damage.
There isn’t a cure for PsA. However, treatment can help improve your symptoms and prevent lasting damage caused by inflammation. Your treatment options will depend on the type and severity of your symptoms. Talk to your doctor about what PsA treatment is best for you.
If your symptoms are mild, you may take nonsteroidal anti-inflammatory drugs (NSAIDs) to control swelling and pain and improve your range of motion. Over-the-counter NSAIDs include ibuprofen (Advil, Motrin) and naproxen (Aleve). Stronger NSAIDs are available with a prescription.
If you have only a few joints that are affected, your doctor may inject a corticosteroid medication directly into the affected area to decrease inflammation.
Moderate to severe PsA symptoms are usually treated with disease-modifying antirheumatic drugs (DMARDs). These medications help to slow joint damage by decreasing inflammation.
Conventional DMARDs help suppress an overactive immune system that may be causing joint damage. The term “conventional” is used to distinguish these drugs from newer, biologic DMARDs, which are a more recent class of medications. Conventional DMARDs used to treat PsA include:
Biologics target specific parts of the immune system that cause inflammation in PsA. Tumor necrosis factor-alpha (TNF-alpha) inhibitors target the TNF-alpha cytokine (an inflammatory protein made by the immune system). TNF-alpha inhibitors used to treat PsA include:
In addition to medications, other types of therapy can help improve hand function and relieve pain associated with DIP PsA. Many of these therapies can be used at the same time as medical treatments. Ask your doctor if therapies such as the following might be right for you:
MyPsoriasisTeam is the social network for people with psoriasis and psoriatic arthritis and their loved ones. On MyPsoriasisTeam, more than 116,000 members come together to ask questions, give advice, and share their stories with others who understand life with psoriatic arthritis.
Do you have DIP psoriatic arthritis? Have any medical or lifestyle treatments particularly helped your symptoms? Share your experience in the comments below, or start a conversation by posting on your Activities page.