Aches come part and parcel with psoriatic arthritis (PsA). Those who have the inflammatory condition often report feeling pain in their hip joints, hands, spine, knees, and feet during disease flares. In addition to these symptoms, roughly 35 percent of people with a psoriatic disease develop enthesitis — inflammation of the connective tissue between tendons or ligaments and bone. This symptom typically appears soon after PsA onset.

Notably, only people with spondyloarthropathies — which include PsA, ankylosing spondylitis, or axial spondyloarthritis — consistently experience enthesitis as a symptom. Other forms of arthritis, like rheumatoid arthritis or osteoarthritis, don’t usually involve enthesitis.

This article will cover the connection between psoriatic arthritis and enthesitis, as well as what you and your rheumatologist can do to manage your symptoms.

What Is Enthesitis?

The human body contains more than 100 entheses, which are the places where tendons or ligaments connect with a bone. They all serve to anchor the soft tissues that bind bones to muscles and that facilitate smooth movement. Enthesitis (also referred to as enthesopathy) occurs when an enthesis and its surrounding tissues become inflamed. Once inflammatory arthritis like PsA sets in, enthesitis can cause musculoskeletal pain or limit a person’s ability to move affected body parts.

Enthesitis mainly impacts the entheseal sites — the points at which tendons and ligaments insert into bones. However, research suggests that enthesitis can affect any areas where hard and soft tissues come together, including enthesis-adjacent tissues such as the fibrocartilage, fat pad, and deeper fascia. Areas affected by enthesitis often become ropey in texture (a condition called fibrosis) or start to solidify through a process called ossification.

Enthesitis in Psoriatic Arthritis

Psoriatic arthritis is a form of spondyloarthritis that affects roughly one-third of all people with psoriasis. Enthesitis is a relatively common symptom of psoriatic arthritis. In fact, it is one of the four main signs of psoriatic arthritis. The others include:

• Peripheral arthritis, which affects large and small joints in the hips, knees, wrists, elbows, feet, ankles
• Spondylitis, which stems from inflammation of the spinal or sacroiliac joints, or those connecting the sacrum and pelvis
• Dactylitis, also known as sausage digits, which can cause swelling so severe that the joint can no longer be independently recognized within a finger or toe

All of these manifestations define how and where people experience symptoms of psoriatic arthritis. They also overlap to a certain degree. For example, although doctors refer to dactylitis as a distinct condition associated with PsA, enthesitis in connective tissue usually contributes to the overall swelling. That said, all have distinctive symptoms.

Symptoms of Enthesitis

Enthesitis often causes pain and limits movement in the affected joints. People with enthesitis often experience aches in their feet, knees, elbows, hips, and shoulders, although enthesis usually only affects one or two locations at a time.

Although enthesitis can affect any enthesis, it most commonly appears at:

• The Achilles tendon, which runs down the back of the heel
• The lateral epicondyles, the bony bump on the outside of the elbow
• The plantar fascia, the ligament connecting the heel to the front of the foot

As one MyPsoriasisTeam member shared, “My worst enthesitis is in my feet. I can’t be on my feet long, let alone walk very far.”

In severe cases, chronic inflammation can cause bone spurs to form near the enthesis (where the spurs are called enthesophytes) or within nearby ligaments (where the spurs are called syndesmophytes). People with enthesitis may also notice pitting — small depressions — in their fingernails or toenails, or their nails may start to lift away from the nail bed.

Does Psoriatic Arthritis Cause Enthesitis?

Enthesitis is a well-established sign of psoriatic arthritis that affects over a third of people with the condition. However, PsA is not the sole (or even direct) cause of enthesitis.

People who don’t have psoriatic arthritis can also develop enthesitis, typically after they have experienced an injury or repetitive trauma. Tennis elbow (lateral epicondylitis), for example, is a common enthesitis-related complaint that occurs after a person overuses their elbow with repetitive movements.

The main difference between enthesitis caused by mechanical (physical) problems and PsA-related enthesis is in how they each heal. Generally speaking, enthesitis related to overuse will fade if a person cares for their injury and avoids the repetitive movement that caused their inflammation. But for a person with PsA, enthesitis is often a chronic problem.

For reasons doctors don’t yet fully understand, people with psoriatic arthritis tend to have a lower threshold for enthesitis development. Mechanical stress, injury, or infection can all trigger long-term inflammation and ultimately lead to full-blown enthesitis. Experts believe enthesitis is better described as an early indicator of psoriatic arthritis, rather than a direct result of the disease.

Research indicates that enthesopathy is heavily involved in the development of PsA. Enthesitis also tends to correlate with worse health outcomes in people who have psoriatic arthritis. One study found that up to 52 percent of people with PsA-related enthesitis have moderate to severe psoriatic arthritis, compared to just 23 percent of those who don’t have enthesitis. Those with enthesitis were also more likely to experience other PsA symptoms, such as nail psoriasis and dactylitis.

There are several risk factors associated with PsA-related enthesitis. Those who have enthesitis in PsA tend to be young, have severe cases of psoriatic arthritis, or have a high body mass index (commonly known as BMI).

Diagnosing Enthesitis in Psoriatic Arthritis

If you have psoriasis on your skin and start to feel pain in your feet, elbows, or hands, you should talk to your doctor immediately about the possibility of PsA. Delaying the diagnosis and treatment of PsA by even six months could lead to permanent joint damage and a substantially lower quality of life.

Diagnosing enthesitis is relatively straightforward most of the time. Your doctor will likely consider your medical history and symptoms. If you have psoriasis, see nail pitting, and are experiencing pain in a telltale location — such as your Achilles tendon — your doctor might be able to make a baseline diagnosis without further testing.

That said, there are some situations where your condition might not be as easy to define. For example, fibromyalgia can cause pain similar to enthesitis pain. To make a differential diagnosis, your doctor might conduct a few physical tests, such as moving your affected limb, or they may order an ultrasound to check for signs of enthesitis.

Enthesitis Treatments for People With Psoriatic Arthritis

Once your enthesitis has been diagnosed, it’s important that you start receiving right away to prevent permanent joint damage.

Enthesitis typically requires intense treatment courses because the condition is resistant to the disease-modifying antirheumatic drugs (or DMARDs) used to treat psoriasis. The approach your doctor recommends will usually depend on the severity of your condition. Some mild cases can even be handled with nonsteroidal anti-inflammatory drugs (NSAIDs) like Advil (ibuprofen), but other cases may need biologics or steroids.

Biologics

If NSAIDs aren’t sufficient, your rheumatologist might suggest biologic therapies — such as Humira (adalimumab) or Remicade (infliximab) — to suppress your overactive immune system.

Steroids

Local corticosteroid injections may reduce disease activity and pain in people with PsA and enthesitis. However, steroids should be used carefully, as they may pose side effects.

Corticosteroids can work quickly for some people. One MyPsoriasisTeam member wrote that prednisone has been “like an absolute wonder drug!” They added, “It takes away almost all of the pain and most of the stiffness, too. I can actually sleep much better and get up without any hesitation in the morning and carry on my life pretty much as I used to.”

Meet Your Team

Living with psoriatic arthritis can be challenging at times, especially if no one in your immediate social circle shares your diagnosis. Having someone who understands the day-to-day struggles can be invaluable.

MyPsoriasisTeam is the social media platform designed to connect and support people with psoriasis and psoriatic arthritis. More than 91,000 members ask questions and share experiences with others who understand life with PsA.

Do you experience enthesis? What has or has not worked in managing it? Share your experiences in the comments below or by posting on MyPsoriasisTeam.