AOSD: Adult-onset Still’s disease

What is adult-onset Still’s disease?

Still’s disease is a systemic autoinflammatory disease with a childhood form, known as systemic juvenile idiopathic arthritis (SJIA), and a similar adult form, called adult-onset Still’s disease (AOSD).

AOSD is a rare type of inflammatory arthritis that causes inflammation resulting in joint damage, high fevers and rashes. AOSD mainly develops in people between the ages of 16-35.1 While there is no cure for AOSD, remission (having little to no visible symptoms) is possible.2

Autoinflammatory diseases, such as AOSD,1 are characterized by an overactive immune system – the body’s defense system against invaders like bacteria and viruses. In AOSD, the immune system mistakenly becomes active when there is no invasion to fight, causing damage to the body’s own cells.



The main symptoms of AOSD include daily high fevers, skin rashes and painful, swollen joints.1 The disease often starts off with a sore throat and people may experience other symptoms including: 1,3,4

AOSD Symptoms

The signs and symptoms of AOSD can be very similar to those of other serious conditions, including other autoinflammatory syndromes, systemic lupus erythematosus (lupus) and a type of blood cancer called lymphoma.4,5

Some people may only experience one bout of the illness and will not go on to experience another flare, while in others the disease persists and may lead to permanent joint destruction.1 When AOSD isn’t recognized and controlled, the chronic inflammation can lead to the deterioration, and eventual destruction, of the affected joints.4 In some cases, excess fluid can build up around the lungs which can lead to breathing problems.4Another serious but very rare complication in people with AOSD is macrophage activation syndrome. The activation of macrophages – cells of the immune system which destroy cells – can overwhelm the whole body, leading to life-threatening systemic symptoms and internal organ failure.5,6


How common is it?

AOSD is very rare – it affects only a few people in every million. Estimates in Japanese and European populations suggest there are between 1 and 34 cases per million people.5Because the disease is so rare and the symptoms vary, AOSD often goes undiagnosed and can be confused with other conditions, making it difficult to work out how common it really is.4 AOSD does not run in families but research has shown that people with certain types of genes may be more likely to develop it.5 Men and women are equally likely to develop AOSD.4


What causes AOSD? 

AOSD is idiopathic, which means the cause is unknown.4 Researchers believe that an abnormal or excessive response to an infection or toxic substance may trigger the disorder in people who also have a genetic predisposition.4,5 AOSD was only recently classified as an autoinflammatory condition due to a better understanding of its underlying mechanisms – specifically the important role of an immune cell called an interleukin2 - but it differs from other autoinflammatory conditions in that it is not believed to be inherited.5 Some researchers think AOSD is a cross between an autoinflammatory condition and an autoimmune disease like rheumatoid arthritis.5


What typically happens over the course of the illness? 

The specific symptoms of AOSD, its severity, the frequency of episodes, and the progression of the disorder vary from one person to another and is difficult to predict. In some individuals, AOSD develops suddenly, disappears almost as quickly, and may not return for many years, if ever. In others, AOSD is a chronic condition that can cause long-term, severe and disabling complications.4


Diagnosing AOSD 

There are no specific tests to diagnose AOSD and differentiate it from similar conditions. As such, diagnosis is normally based on a review of current symptoms, medical history and a physical examination. Doctors who specialize in skeletal and systemic autoinflammatory diseases are known as rheumatologists and are often best placed to help to diagnose and treat AOSD.

Tests that can aid in diagnosis include blood tests and x-rays, which reveal changes to the bones or joints, or enlargement to the spleen or liver. Blood tests may also reveal certain changes associated with AOSD.2,4


There are several treatment options for AOSD. Doctors will usually first prescribe nonsteroidal anti-inflammatory drugs (NSAIDs) to help reduce pain and inflammation.

For longer-term treatment, corticosteroids can be used to treat symptoms but is associated with a variety of side effects. Methotrexate is often prescribed alongside corticosteroids as it allows lower doses of corticosteroids to be used. Another option are biologics, drugs that block the activity of some of the substances involved in causing the disease. It’s also possible that doctors will recommend taking more than one type of drug to keep the condition under control. In chronic cases, medication may need to be taken after symptoms go away. This is important to keep inflammation under control to prevent further damage to joints and other organs.2,4

Good communication with doctors & specialists is important to ensure that you fully understand what treatment options are available to you. Read more on what to prepare for a doctor’s appointment here .


Living with AOSD 

Being diagnosed with a disease like AOSD is a life-changing event, as its impact goes well beyond the physical symptoms. The frustration and pain of adapting to a life with AOSD can take its toll on a patient’s mental wellbeing, relationships, hobbies, and work. It is important to recognize that it takes time to “re-calibrate”. For more information and advice, visit our section on Lifestyle or read how other patientsare living with similar diseases.

Find more information and support on AOSD and autoinflammatory diseases here.


  1. Arthritis Foundation. Adult Still’s Disease. Available from: (accessed May 2020)

  2. Jamilloux Y, Gerfaud-Valentin M, Henry T et al. Treatment of adult-onset Still’s disease: a review. Ther & Clin Risk Manage 2015;11:33–43.

  3. Cush JJ. Autoinflammatory syndromes. Dermatol Clin. 2013;31(3):471–480.

  4. National Organization for Rare Disorders. Adult onset Still’s Disease.  Available from: (Accessed May 2020)

  5. Gerfaud-Valentin M, Yvan Jamilloux Y, Iwaz J et al. Adult-onset Still’s Disease. Autoimmune Rev 2014;13;708–722.

  6. Arthritis Foundation. Understanding Macrophage Activation Syndrome. Available from: (accessed May 2020).
Kids Corner

Want to help your child understand their illness ? Why not visit Kids Corner with your child and read Paula and Tim's explanation of autoinflammatory disease and their experience of attending school and after school activities with their condition.

Life with Periodic Fevers

June 2016 - GLDEIM/ACZ885/0075