Several components make up the joints of the body, including bones, muscles, tendons, ligaments, and entheses. Enthesitis occurs when an enthesis, the site where ligaments and tendons connect to the bone, becomes inflamed.

There are more than 100 entheses throughout the body, and enthesitis can affect any of them.

The main symptom of enthesitis is a burning or intense pain in and around the affected joints. A person may also notice swelling or stiffness.

Anyone can develop enthesitis, usually through the overuse of joints. However, up to 50% of people living with psoriatic arthritis (PsA) develop enthesitis. It is more likely to become chronic in people with PsA, which means it will not go away with treatment such as ice packs.

This article discusses psoriatic arthritis and enthesitis and the symptoms that the conditions can cause.

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People with PsA are more likely to develop enthesitis, and it is more likely to be chronic in this group.

People who are not living with PsA can experience enthesitis too. According to the Arthritis Foundation, “tennis elbow” can bring about the inflammation and is one of the most common causes after PsA.

The difference for people who experience this type of enthesitis is that rest, ice, and activity change typically make the pain go away. A person living with PsA is more likely to experience ongoing pain because this condition makes the immune system continually cause inflammation without complete healing.

People living with PsA often develop enthesitis early, but they may have it at any point.

Enthesitis as a distinguishing feature of PsA

PsA is part of a family of arthritis known as spondyloarthropathies. According to the American College of Rheumatology, the term spondyloarthropathy refers to a family of related rheumatic diseases that cause arthritis.

Spondyloarthropathies differ from other forms of arthritis because they often affect the entheses. In fact, doctors usually consider enthesitis a defining feature of PsA and other forms of spondyloarthropathies.

This is why doctors often use the presence of enthesitis to help differentiate diagnoses of PsA from those of other types of arthritis, such as rheumatoid arthritis.

Learn more about the differences between PsA and rheumatoid arthritis here.

Does having enthesitis mean PsA is worsening?

Enthesitis does not necessarily mean that a person living with PsA is experiencing a worsening condition. The condition can present itself in mild cases of PsA as well as severe ones.

However, it could indicate that PsA is currently active in a person because PsA may occur in symptom flare-ups.

Enthesitis can cause similar symptoms to PsA itself. According to the Arthritis Foundation, common symptoms of enthesitis include:

Location

One of the most common areas where enthesitis can affect a person is where the Achilles tendon attaches to the back of the heel. However, the symptoms can occur in several joints around the body. Other common sites include:

  • hips
  • shoulders
  • where the ribs meet the breastbone
  • elbows
  • knees
  • spine

Overlap with PsA symptoms

PsA can cause similar symptoms to enthesitis. Some similar symptoms include pain, stiffness, or throbbing in one or more joints, and reduced range of motion in a joint.

In addition, a person may feel fatigued or experience redness and pain in the eye.

It is important to note that due to the high prevalence of enthesitis among people with PsA, enthesitis may cause these symptoms, especially if they occur in the same joints repeatedly.

Learn more about PsA symptoms here.

Currently, there are no standards regarding the exact tests a doctor will use to diagnose enthesitis, although doctors may suggest imaging tests, including an ultrasound. However, as the Arthritis Foundation explains, an examination of symptoms is often enough for a diagnosis.

The signs a doctor may look for include:

  • pitting or separation of the nail bed
  • pain in the back of the heel
  • swollen fingers or toes

A doctor may also use standard questionnaires to check for other conditions, such as fibromyalgia. A doctor can also confirm enthesitis by applying pressure to the joint area during movement that reproduces the pain.

When a doctor diagnoses enthesitis in someone with PsA, they may also need to make changes to a person’s treatment plan. The Arthritis Foundation says disease-modifying antirheumatic drugs to treat PsA, such as methotrexate, have little or no effect on enthesitis.

Doctors may recommend different treatment plans depending on a person’s individual circumstances, including:

  • Milder cases of enthesitis: A doctor may recommend the use of nonsteroidal anti-inflammatory drugs, such as ibuprofen.
  • More severe or widespread cases of enthesitis: A doctor may recommend using biologics, such as a TNF inhibitor. Biologics can help reduce the activity of enthesitis, provide symptom relief, and prevent damage.
  • If enthesitis only affects one area: Doctors may recommend a corticosteroid injection around the joint area. The injection can reduce inflammation and provide symptom relief.

At-home treatment

In addition to medical treatments, a person may find relief for their symptoms with some home remedies. Some potentially helpful therapies include:

  • maintaining a moderate weight
  • using compression socks, braces, or other devices that help reduce swelling
  • reducing salt consumption
  • cold or hot therapies
  • elevating the affected joint
  • avoiding smoking

PsA belongs to the spondyloarthropathy family of conditions, which are rheumatic conditions that can cause arthritis. Researchers in a 2016 study note that enthesitis is a key feature of spondyloarthropathies.

In addition to PsA, spondyloarthropathies include:

  • Peripheral spondyloarthritis: This condition mainly affects the legs and arms.
  • Axial spondyloarthritis: Mainly affects the spine.
  • Enteropathic arthritis: This condition mainly affects the digestive system.
  • Reactive arthritis: A type of inflammatory arthritis that usually occurs after a bacterial infection, but viral infections can also trigger it.

PsA is part of a family of arthritis conditions that typically cause enthesitis. Enthesitis can cause symptoms similar to PsA, including painful joints, but it directly affects the area where the tendons and ligaments meet the bone.

Doctors may use the presence of enthesitis to diagnose PsA as opposed to another type of arthritis, such as rheumatoid arthritis.

Treatment options may be different for enthesitis than for PsA, which also means it is important to make a proper diagnosis. A doctor will recommend treatments that can both help reduce the activity of the disease and decrease symptoms.