This website is designed to give you the information you need to understand Still's disease, and the critical signs to look out for. Please read on to find out more about the condition, the signs and symptoms of Still's disease, how it is treated, and the red flags associated with Macrophage Activation Syndrome (MAS).

This website and accompanying resources have been developed by Juvenile Arthritis Research - a UK charity supporting children and families affected by Juvenile Idiopathic Arthritis and Still's disease.

You can download the information on this website as a leaflet here.

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What is Still’s disease / Systemic JIA?

MAS: Macrophage Activation Syndrome

What's in a name?

Still’s disease (also called Systemic Juvenile Idiopathic Arthritis, or sJIA) was named after George Frederic Still. In 1896, he was the first person to describe a form of childhood arthritis that was associated with fever. Until recently the international classification called it sJIA as a distinct form of arthritis that starts in childhood. However, the term ‘Still’s disease’ may be better – because you can have the condition without any inflammation in the joints. When diagnosed in adults, this condition is called Adult Onset Still’s disease (AOSD). In this leaflet, we will mainly refer to the condition as Still’s disease.

What is Still’s disease / Systemic JIA?

Your immune system is designed to fight off infections like bacteria and viruses that try to invade your body. It is very complex and is made up of lots of different parts which usually work together to keep you healthy.

Some parts (called the adaptive immune system) are targeted against specific infections. These parts develop throughout your life, are very specific, but can take time to be effective against invaders. Other parts are more general (called the innate immune system). The innate system usually works quickly when you get an infection by raising your temperature (called a fever), and releasing chemical messengers to get other parts of your immune system working. This causes general inflammation.

In Still’s disease, the innate part of the immune system becomes overactive. This is called an autoinflammatory disorder. It can affect different parts of your body and doesn't only affect one type of cell or organ (this is known as systemic). Still’s disease is also complex, because lots of different parts of your immune system get involved and lots of different chemical messengers can be released. So, Still’s disease is considered to be a complex autoinflammatory disorder.

What is JIA?

You may have heard of the term ‘JIA’ or Juvenile Idiopathic Arthritis. It is a group of different disorders in which the immune system causes inflammation in the joints. Still’s disease or sJIA is one subtype of JIA, and around 10% of children with JIA have sJIA. You can find out more about the other types here.

Where can I get support?

If you or your child is affected by Still’s disease / sJIA, we are here for you. You can request a free Little Box Of Hope support pack from us at Juvenile Arthritis Research, full of information and resources designed to support you and your family on your journey.

Click here to request a free Little Box Of Hope support pack from Juvenile Arthritis Research (UK addresses only).

Click here for other information and resources (online and printable, including mental health support).

In this webinar, Professor Paul Brogan gives an overview of sJIA/Still's Disease including the naming of the condition, signs and symptoms of the condition, an overview of treatment pathways, as well as what to look out for in the early signs of a flare and when to seek help. Prof Brogan is a Professor of Vasculitis at University College London in the Department of Infection, Immunity & Inflammation, and an honorary consultant in paediatric rheumatology at Great Ormond Street Hospital.

"I wanted to say thank you so much for the webinar. I've learnt more about Still's disease in an hour than I have in months."
Parent of a child with Still's disease.

How do I know if I have Still’s disease?

To make a diagnosis of Still’s disease, your doctor will examine you and talk to you and your family about your symptoms. They will want to know how long your symptoms have lasted and may do some tests like blood tests or scans to rule out conditions that can look similar. There is no single test for Still’s disease so your doctor may test for several other conditions to rule them out. Still’s disease is usually diagnosed by a rheumatologist or a paediatric rheumatologist. If any other doctor thinks you might have Still’s disease they should get a rheumatologist to check urgently to confirm the diagnosis and start treatment.

Signs and symptoms of Still’s disease

Spiking fevers that come and go. Your body temperature can sometimes drop below normal temperature, too.

‘Salmon pink’ rash that comes and goes with the fever – this can be hard to spot, especially in different skin tones.

Lymph glands may be swollen.

Inflammation may be evident on blood tests.

Joint inflammation (sometimes visible, and sometimes not) and not always present - this is known as ‘arthritis’.

There is a high risk of MAS (Macrophage Activation Syndrome - also known as a ‘cytokine storm’ or HLH – haemophagocytic lymphohistiocytosis). Here the fever becomes persistent, the blood tests change, and people can become very unwell. MAS is a medical emergency.

Seek help immediately. Further information about MAS is below in the red section.

Still’s disease has two main stages

The first (called ‘early autoinflammation’) is driven by a chemical messenger called interleukin-1 (or IL-1). It shows mainly as fever and rash, there may be no arthritis.

The second is prolonged (or chronic) inflammation, which is driven by the chemical messengers IL-6 and IL-17. In this stage, arthritis is more common, and the rash and fever may continue.

Treatment

Prompt treatment of Still’s disease is vital! At the moment, NHS guidance says that a child with Still’s disease who has no signs of MAS must start treatment with methotrexate. This can be effective against joint inflammation, but research has shown it is not effective against the systemic nature of Still’s disease.

Current NHS guidance requires that methotrexate has to fail to work (or the child be intolerant to it) before they can move to other medicines. Ideally we want to see all children and young people who have Still’s disease to start on the best treatment straight away that will target all aspects of their condition. We are campaigning for this - contact us if you wish to help. If a child has any signs of MAS, treatment usually starts with a medicine called Anakinra, which works against the IL-1 chemical messenger pathway.

Other treatments that have been shown to be effective include Tocilizumab (which targets the IL-6 pathway) and Canakinumab (which works against IL-1). Other studies have shown other medicines to be effective, too. Many children with Still’s disease will also be given steroids, as this can help reduce inflammation quickly.

Outcomes

Many children with Still’s disease go on to live full and active lives. Over 80% reach ‘clinically inactive disease’ (where the disease is no longer causing any symptoms) and around a third stop medication completely and remain in remission. There is a long-term risk of developing lung disease if you have Still’s disease / sJIA. You should monitor this with your healthcare team throughout your life, even if your condition seems to get better.

Becoming an adult with sJIA / Still’s disease

Once you have this diagnosis, you are likely to have it for life. For most people their disease becomes inactive with the right medication. However, you still have the condition. This is important to remember, because you can flare (a period of time when your symptoms worsen) at any point in the future. Nobody can predict if and when that might happen.

If you do flare when you are older, you must tell your doctor that you have Still’s disease / sJIA so they can give you the right medication. A flare can develop into MAS quite quickly, so early treatment is important. You are also at risk of lung disease. If you experience breathing difficulties at any time, or shortness of breath, or notice your fingers are swelling at the fingertips, speak to your doctor and tell them you have Still’s disease and ask them to check for lung disease. They can do this with a CT scan.

MAS: Macrophage Activation Syndrome

If you have Still’s disease and have any worries or concerns about your condition, speak to a member of your family or your doctor or medical team.

MAS can develop very quickly and can be fatal. Prompt diagnosis and early treatment are essential.

Know the signs and symptoms

(someone with MAS may not have all the symptoms):

High fever that is persistent, meaning high all the time.
Rash.
Reduced level of alertness, or increased level of confusion.
Loss of appetite.

MAS can sometimes be triggered by an infection or a change in medication, even if your Still's disease / sJIA is otherwise in remission.

If you experience ANY of these symptoms, seek urgent medical help:

Speak to your rheumatology team (do not wait for your next appointment).

Go to your local hospital's emergency department, tell them you have Still’s disease / sJIA and ask them to check for MAS. This can be done with a blood test (full blood count and measure ferritin levels).

Treatment may include

Steroids
Anakinra
Ciclosporin
Etoposide
Antibiotics, until an infection is ruled out
New medications are continuing to be developed

FOR HOSPITALS

A person with Still’s disease/sJIA is at higher risk of developing Macrophage Activation Syndrome (MAS).

If not treated promptly and effectively, MAS can cause critical illness and even death - act immediately.

Knowing the signs and symptoms and treating early can save lives.

Step 1: Take a blood test and measure ferritin, and check for signs of infection.

Step 2: If ferritin is >400, call your on-call rheumatology or paediatric rheumatology team immediately.

Other blood results may be abnormal, but do NOT wait until all the clinical criteria are met as this can result in a delay in diagnosis and treating MAS.

Remember:
Early treatment of MAS can save lives

Hospital staff may wish to review the guidance promoted by the British Society for Rheumatology about identifying, treating and monitoring MAS. However, the priority is to contact the specialist rheumatology or paediatric rheumatology team. Medical professionals may also find information from HIHASC useful.

We need your help

Juvenile Arthritis Research is committed to changing the lives of children, young people and adults with all forms of Juvenile Idiopathic Arthritis and Still’s disease. Our charity undertakes research, raises awareness and provides support.

If this leaflet has helped you, please help us to continue our work by donating or fundraising for us. Start your supporter journey by visiting www.jarproject.org/give or complete this form to contact us.

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