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Psoriatic arthritis (PsA) is a kind of inflammatory arthritis that can affect people with psoriasis. Between 20 to 30 percent of individuals with psoriasis also have PsA.

PsA is characterized by pain, swelling, and stiffness in the joints. Some individuals with PsA will also experience something called enthesitis.

Enthesitis happens when the area where ligaments and tendons connect to bone becomes inflamed. Keep reading to learn more about PsA enthesitis, its symptoms, and how it’s diagnosed and treated.

The entheses are the areas where your ligaments and tendons insert into bone. They’re very important for joint movement, as they help to distribute mechanical forces as well as provide support.

There are over 100 entheses in your body. When one or more entheses become inflamed, it’s called enthesitis.

Enthesitis is a common feature of both PsA and axial spondyloarthritis. It’s estimated to affect about 35 percent of — roughly 1 in 3 — people that have PsA.

Because enthesitis is more frequent in PsA compared to most other types of arthritis, it can be a good indicator of PsA. So, if you visit your doctor because of joint symptoms, they may look for signs of enthesitis to help make a diagnosis.

Some research has indicated that people with PsA that have enthesitis experience higher disease activity. Additionally, a 2017 analysis found that the severity of enthesitis was associated with increased joint damage.

Enthesitis due to PsA can also have other effects. For example, a 2020 survey found that, compared to people with PsA who didn’t enthesitis, those with enthesitis reported:

  • higher amounts of pain
  • increased level of disability
  • lower quality of life
  • a negative impact on work

The main symptoms of enthesitis are tenderness, pain, and stiffness. Because the entheses are important for movement, you’ll notice these symptoms more when you’re moving.

Some visible symptoms of enthesitis are redness and swelling in the affected area.

Commonly affected areas

Enthesitis typically impacts only one or two areas of the body at the same time. Some of the most commonly affected areas are the:

  • back of the heel (Achilles tendon)
  • bottom of the foot (plantar fascia)
  • elbow (lateral epicondyles)

Inflammation of fingers or toes

The presence of enthesitis can also happen with another common symptom of PsA called dactylitis. This is a painful inflammation of a finger or a toe.

Changes in fingernails and toenails

In people with PsA, enthesitis is also associated with changes in the fingernails, toenails, or both. Nail changes can include:

Bone spurs

The inflammation from enthesitis can be long lasting (chronic). When this happens, it’s possible for bone spurs to develop in the affected area.

It’s believed that enthesitis happens due to physical stress that’s placed on an area. Over time, damage accumulates at the affected area.

When your immune system senses that an area has become damaged, it releases chemicals called cytokines. These can result in inflammation.

In a healthy individual, enthesitis can sometimes happen due to overuse of a joint, such as in tennis elbow or Achilles tendonitis. It typically goes away with rest, icing, and the use of nonsteroidal anti-inflammatory drugs (NSAIDs).

However, in a person with PsA, the immune system doesn’t function properly, leading to increased levels of inflammation. This contributes to persistent or chronic inflammation at the entheses.

Some individuals with PsA may be at a higher risk of enthesitis. For example, a 2017 cohort study found that the following factors boosted enthesitis risk:

There isn’t a specific laboratory test that can be used to diagnose enthesitis. Your doctor will ask about your medical history as well as the type of symptoms you’re experiencing and where they occur.

They’ll also perform a physical examination, during which they’ll do things like:

  • check for redness or swelling around the affected joint
  • apply a small amount of pressure to the affected area to assess tenderness and pain
  • evaluate the affected joint’s range of motion
  • look for other PsA symptoms that often happen with enthesitis, such as dactylitis or nail changes

Imaging tests can also be used to help your doctor look for inflammation around the entheses. Some examples of imaging technologies that may be used are:

There are a few different treatment options for enthesitis due to PsA. Most are the same types of treatments that are used to treat PsA in general.

Medical treatments

A potential early treatment for enthesitis are high doses of NSAIDs. However, not all instances of enthesitis will respond to NSAIDs. In this case, treatment with a biologic drug may be necessary.

A biologic is a type of disease-modifying antirheumatic drug (DMARD) that targets specific parts of the inflammatory process. A few examples of biologic drugs that may be used to treat enthesitis are:

If enthesitis is only impacting a single joint, it’s possible that a corticosteroid injection in the affected area may be an option. This can alleviate inflammation and help with healing.

Home remedies

In addition to the treatments above, you can try the following things at home to help with PsA enthesitis:

  • Exercise. Doing gentle stretches or exercises may help to reduce pain and stiffness. Be sure to ask your doctor about appropriate stretches. It’s also possible that they’ll refer you to a physical therapist.
  • Hot and cold. You may find alternating between a warm and cold compress to be helpful. Applying a warm compress to the affected area can reduce stiffness while using a cold compress can reduce swelling.
  • Orthotics. If enthesitis is impacting your foot, you may want to consider getting shoe inserts to help provide extra support.

Enthesitis is inflammation in the area where ligaments and tendons connect to bone. It’s quite common in individuals with PsA.

The symptoms of enthesitis can include tenderness, pain, and stiffness. You may also notice swelling and redness. Enthesitis also commonly happens with other PsA symptoms like nail changes and dactylitis.

Enthesitis is treated using many of the same treatments as PsA. Since this condition has been associated with higher PsA disease activity and joint damage, be sure to see a doctor for evaluation and treatment if you think you have enthesitis.