Psoriatic arthritis mutilans is a rare and severe type of psoriatic arthritis. The condition ultimately causes bone loss in the affected joints, which can make it impossible to bend or straighten them.

Psoriatic arthritis mutilans is the most severe form of psoriatic arthritis. It causes joint damage and the destruction of bone tissue. This subtype of arthritis is sometimes called “opera glass hand” or “telescopic finger.”

Psoriatic arthritis mutilans typically occurs in the hands and sometimes affects the fingers, wrists, and feet. It’s considered rare.

Keep reading to learn what symptoms to look out for, what causes this condition, and more.

Psoriasis and psoriatic arthritis

As of 2020, psoriasis affects at least 7.55 million Americans. It’s one of the most common autoimmune diseases in the United States. About 20 to 30 percent of people with psoriasis develop psoriatic arthritis.

Of the people with psoriatic arthritis, 2 to 20 percent develop psoriatic arthritis mutilans.

There are five types of psoriatic arthritis, and psoriatic arthritis mutilans is considered the most severe. To understand how the condition develops, it’s helpful to understand how psoriatic arthritis occurs.

You usually develop psoriatic arthritis if you’ve already had psoriasis. Psoriasis is caused by an autoimmune response in your body, where your immune system attacks your healthy cells. This can cause inflammation throughout the body, including the joints. It’s the main cause of arthritis.

Long-term inflammation of your joints can cause permanent damage. Certain bones, like those connected to frequently used joints, may start to erode. When this happens, it’s known as psoriatic arthritis mutilans.

Psoriatic arthritis mutilans can be caused or triggered by:

  • physical trauma to the joint in people with psoriatic arthritis
  • other environmental triggers
  • genetics, which may play a role in the development of psoriatic arthritis

People can develop bone loss in one or more joints.

Psoriatic arthritis mutilans is a severe subtype of psoriatic arthritis. People who develop psoriatic arthritis may experience the following symptoms:

  • stiff joints
  • joint pain
  • decreased range of motion
  • swelling
  • skin rash
  • nail deformity

If you develop psoriatic arthritis mutilans, the bone in the affected joints will begin to disappear. This can result in symptoms that may include:

  • inability to straighten or bend the affected joint
  • shortened joints
  • loose skin in affected joints

Over time, as the affected joints shorten, loose skin may develop in the affected areas. The loose skin can retract and becomes loose and mobile.

Psoriatic arthritis mutilans is rare, so there’s little evidence on how to predict whether it will develop.

So far, research into the risk factors for psoriatic arthritis is inconclusive. Childhood obesity and diagnosis of psoriasis at a young age may be risk factors. But the only strong indicator of developing psoriatic arthritis is family history of the condition.

Potential risk factors for psoriatic arthritis can include:

  • genetics
  • family history
  • history of infection requiring antibiotics
  • skin trauma
  • joint trauma

According to the National Psoriasis Foundation, 30 percent of people with psoriasis develop psoriatic arthritis. However, the diagnosis may not always occur in that order, and some people with psoriatic arthritis don’t develop psoriasis.

To diagnose psoriatic arthritis mutilans, the doctor will first confirm that you have arthritis. After checking your joints for signs of swelling or tenderness, they’ll likely conduct diagnostic testing.

The doctor may order lab tests to check for inflammation. The doctor will also likely recommend an X-ray or other imaging test to assess joint damage.

Once the doctor has diagnosed you with arthritis, they’ll test a blood sample to find out what kind of arthritis you have. For example, if the rheumatoid factor (RF) and cyclic citrullinated peptide (CCP) antibodies are in your blood, you may have rheumatoid arthritis (RA).

At this time, there isn’t a lab biomarker for psoriatic arthritis or the psoriatic arthritis mutilans subset. Psoriatic arthritis mutilans is diagnosed by checking the severity of the bone damage. There are very few conditions associated with such severe bone loss.

People with this condition may have certain features that can include:

  • telescoping of one bone into another
  • shortened digits
  • pencil-in-cup deformity, where the bone appears sharp on an X-ray and the connecting bone has a cup shape
  • osteolysis, a condition in which bone tissue degrades and becomes softer
  • other nearby joints may be affected, like the small joints of the hands

Psoriatic arthritis mutilans is a progressive disease. The sooner it’s diagnosed, the more its progression may be slowed. Treatment goals can include managing your symptoms and helping maintain or improve your quality of life.

Treatment options can vary depending on disease progression, co-occurring conditions, and the parts of the body affected.

Treatment options can include:

Many treatments include the DMARD methotrexate (Trexall), a TNF inhibitor, or both.

Methotrexate may ease your arthritis symptoms. But it’s unclear whether it can slow the progression of the disease.

TNF is a protein in the body responsible for inflammation. According to the American College of Rheumatology, TNF inhibitors can help reduce inflammation and keep the disease from getting worse. Suppressing inflammation keeps joints from feeling stiff or painful. Reducing inflammation may also help restore joint function.

A 2017 review suggests that switching between anti-TNF medications in the event that one becomes less effective may be an effective treatment strategy.

This type of arthritis can cause permanent disability if it’s not treated. But a diagnosis of psoriatic arthritis mutilans means something different today than in the past when it was called “opera glass hand.”

Your outlook can improve dramatically when you detect and treat psoriatic arthritis. Early treatment can prevent bone loss.

Bone tissue can’t be fully restored. But treating your psoriatic arthritis can slow the damage to your bones. Instead of losing the use of your fingers or toes, treating can help keep them functioning.

Diseases that are difficult to predict can be difficult to prevent. There’s currently no way to prevent psoriatic arthritis.

Detecting psoriatic arthritis early and seeking treatment can help prevent and slow bone damage.

If you find out you have a family history of psoriasis, talk with a doctor. If you experience symptoms of arthritis, especially if you have psoriasis, talk with a doctor.

Psoriatic arthritis mutilans is a severe subtype of psoriatic arthritis. It results in bone loss and damage and can cause joint stiffness and a loss of mobility.

If you experience symptoms of psoriatic arthritis, it is important to seek medical attention. Early detection and treatment can help preserve joint function.