How Do I Know If I Have Adult-Onset Still’s Disease?

Reviewed by: HU Medical Review Board | Last reviewed: February 2023 | Last updated: July 2023

Adult-onset Still’s disease (AOSD) is a rare inflammatory condition that affects mostly the joints. But it can affect many other areas of the body too. AOSD is an autoimmune condition in which a person's immune system attacks itself by mistake.1,2

AOSD occurs in people over the age of 16 years old. Most people will be diagnosed between 16 and 35 years old. However, it is possible to be diagnosed later in life. All genders are equally likely to be diagnosed.1,3,4

Challenging, nonspecific symptoms

Each person’s symptoms can vary, and many AOSD symptoms are nonspecific. This means that they can be a sign of several different conditions, not just AOSD. Nonspecific symptoms can make it hard to diagnose what is truly going on.1,3,5

Some common symptoms are fever, joint or muscle pain, fatigue, and sore throat.


People with AOSD often have regular fevers. These fevers reach 102 degrees Fahrenheit or higher. The fevers come and go. For many people, these fevers happen at least once a day for 2 weeks or more. The most common times of day for fever are in the afternoon or evening. It is also possible to have more than one fever in a day.1-3

Joint and muscle pain

AOSD is a type of arthritis. AOSD-related immune system changes cause damage to the joints. Joint pain is a common early symptom of AOSD. This joint pain can come before, during, or after the fevers. Muscle pain is common in people with AOSD, too. It is usually worse during times of fever.1-3

The number and type of joints involved in AOSD can vary. In some cases, a few joints may be affected (oligoarthritis). In other cases, joint issues may be more widespread. The number of joints and severity of symptoms can change over time.1-3

Specific joints that may hurt in people with AOSD include:1-3,5

  • Knees
  • Wrists
  • Elbows
  • Ankles
  • Fingers
  • Shoulders


Being fatigued is a feeling of overwhelming tiredness that does not get better with rest. Fatigue can be a sign of chronic inflammation, which happens with AOSD. Fatigue may be a sign of many different health issues.1,3

Fatigue can make it hard to get through the day or complete tasks. It can also take a toll on mental and emotional health.1,3

Sore throat

It is not uncommon for the lymph nodes in the throat to get bigger in people with AOSD. The lymph nodes are tiny structures throughout the body where immune system cells live. When you are sick, your lymph nodes can get bigger as the immune system builds up a response.1-3

When lymph nodes get bigger or swell in the neck, a sore throat may result. Swollen lymph nodes can be a sign of infection, cancer, autoimmune issues, and more.1-3

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Other symptoms

There are other symptoms possible with AOSD. These include issues with the liver, like changes in its size or function. It is also possible to have inflammation of the heart or lungs. This inflammation can affect how well these organs function and can cause trouble breathing or heart failure.1,2

Lung problems are more common in people who have macrophage activation syndrome (MAS), a potential complication of AOSD. MAS can be life-threatening. People with MAS have widespread inflammation, low blood cell counts, high levels of fat in the blood, and liver issues.1-3

How is AOSD diagnosed?

Right now, there is no single test that can diagnose AOSD. Instead, your doctor will try to rule out other health issues. Because the symptoms of AOSD are non-specific, there may be many other conditions that need to be considered.1-5

Your doctor will ask you about your symptoms, other medical problems, drugs you take, and more. The answers to these questions will help them determine what tests might be best. They will also do a full physical exam.1-5

From there, your doctor may recommend a few blood tests. Some of these tests may look for signs of inflammation or infection. These tests look at:1,3,5

  • Blood cell counts (CBC)
  • C-reactive protein (CRP)
  • Erythrocyte sedimentation rate (ESR)
  • Ferritin (a type of iron we store in the body)

Some blood tests also look for autoimmune markers. One example is rheumatoid factor, which is common in rheumatoid arthritis. Rheumatoid arthritis and AOSD are 2 different issues.1,3,5

Your doctor may also suggest imaging tests like X-rays or magnetic resonance imaging (MRI). These images can help look for signs of joint damage or injury. However, early on in AOSD, there may not be much visible damage.1

By taking into account your symptoms, physical exams, blood tests, and imaging, your doctor can make a final diagnosis of AOSD. This process may take time as your healthcare team sorts through all the pieces of information collected.

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