Adult-Onset Still's Disease

Adult-onset Still's disease is also called adult Still's disease and Wissler-Fanconi syndrome. This form of arthritis has no known cause. Some 76% of people are diagnosed with this disease before the age of 35. It seems to affect men and women equally.


What is adult-onset Still’s disease (AOSD)?

AOSD is a form of systemic juvenile idiopathic arthritis, also known as juvenile Still’s disease, which affects adults and not children. Initially, AOSD might cause pain in just a few joints, but over time it can spread to other joints and even the entire body. The disease can become disabling in some cases.

The frequency of symptoms varies among individuals. For some, the disease goes into remission after one episode that lasts about a year and symptoms never appear again. For others, a second episode doesn’t occur until years later. In some cases, the disease develops into chronic arthritis.

Both the adult and juvenile versions of the disease were named after a British physician, Sir George F. Still. The adult form is known by other names, such as adult Still’s disease and Wissler-Fanconi syndrome.


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Who is most likely to contract adult-onset Still’s disease (AOSD)?

Slightly more than 1 person per 100,000 people are affected each year. Males and females 16- to 35-years old are mostly likely to contract AOSD. The condition seems to affect men and women equally, although some studies suggest women are affected slightly more than men. Seventy-six percent of people with AOSD are diagnosed before turning 35, and less than 9% are diagnosed after 50.

Symptoms and Causes

What are the symptoms of adult-onset Still's disease (AOSD)?

Usually, the first symptoms include a fever that spikes to 102.2 degrees Fahrenheit or higher once or twice a day and a pinkish or salmon-colored rash on the arms, legs, chest, back and abdomen. The rash disappears when the fever drops. The rash might or might not be itchy. Other symptoms can include:

A few weeks after these symptoms, your muscles and joints, especially knees and wrists, start swelling, stiffening and aching. The disease can also affect the ankles, shoulders, elbows and fingers. This phase lasts about two weeks.


Does adult-onset Still's disease (AOSD) resemble other conditions?

AOSD shares the symptoms of fever, rash, and abdominal and joint pain with auto-inflammatory syndromes and autoimmune disorders. Immune systems that do not function normally cause both auto-inflammatory and auto-immune system problems. The first type of problem involves excessive swelling and soreness. Auto-immune system problems mean that your immune system, which is supposed to protect your body against illness, instead attacks healthy tissue.

Other disorders that look like AOSD include:

What causes adult-onset Still's disease (AOSD)?

We don't know what causes AOSD. Some research indicates that it is caused by a virus, toxic substance, or infection. Other research points to an immune system that does not work correctly and attacks healthy tissue or has an extreme reaction to an infection. Scientists don't believe that AOSD runs in families.


Diagnosis and Tests

How is adult-onset Still’s disease (AOSD) diagnosed?

No single test can identify AOSD. Because of this, tests might be done that exclude other diseases, especially infection and cancer. Doctors diagnose it after reviewing a person's medical history and symptoms, which include arthritis lasting at least 6 weeks.

Blood tests can rule out other conditions and diseases, and might even detect blood-cell level changes consistent with ASOD. Ferritin levels might be higher with ASOD than other similar diseases.

X-rays can spot damage to muscles and joints caused by the disease’s inflammation. Unfortunately, because the condition is rare, it can be undiagnosed or misdiagnosed.

Management and Treatment

How is adult-onset Still’s disease (AOSD) treated?

In the disease’s early stages, doctors can prescribe nonsteroidal anti-inflammatory medications, like ibuprofen and naproxen, and steroid hormones to reduce inflammation, pain and fever, and prevent long-term damage to joints. If steroids are used, other drugs are given to guard against possible negative side effects from steroids, such as opportunistic infection, stomach ulcers and weak bones.

Painkillers like codeine and tramadol can also help. In severe or chronic cases, doctors can prescribe immunosuppressive drugs, which stop the immune system from attacking healthy tissue. Even after symptoms stop, doctors may have people with this condition continue taking the medications to keep inflammation under control. There is no drug combination that works for every single case.

Are researchers exploring new drugs and treatments for adult-onset Still’s disease (AOSD)?

Yes. A class of drugs being tested include biological response modifiers. These drugs block the activity of substances called cytokines secreted by the immune system. Cytokines are believed to play a role in AOSD.

A drug called anakinra interferes with interleukin-1, which is a protein that may be part of the cause of AOSD. Anakinra has been tested on some folks with AOSD and has brought dramatic improvement.

TNF-alpha antagonists are drugs that halt the activity of a protein that contributes to inflammation. They have been used for arthritis and are under study for AOSD.

Can complications develop from adult-onset Still’s disease (AOSD)?

If left untreated, AOSD can cause joints to break down. The spleen and liver can become enlarged. Membranes around the heart or heart muscle, and along the chest wall, can swell, causing fluid to collect in the lungs. Once the heart and lungs are involved, you might have trouble breathing. In some cases, breathing difficulty is so subtle that only a doctor would notice it during an exam.gle case.

Outlook / Prognosis

What is the long-term prognosis for adult-onset Still’s disease (AOSD)?

For about one-third of people with the condition, AOSD never recurs after the first time it happens and is treated. Another one-third will experience relapses, although these later flare-ups are usually less severe. For another one-third, the disease will turn chronic and last years. If you are someone with chronic AOSD, you might need immunosuppressant drugs to protect major organs.

Once AOSD is controlled, you can feel healthy and live a normal life. Steroid treatment might cause weight gain and mood changes, but as steroid dosages are reduced during treatment, those problems will disappear.

Medically Reviewed

Last reviewed on 02/09/2021.

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