Still’s Disease

Still’s disease is a rare inflammatory condition that causes daily high fevers, a distinctive rash, and joint pain. This disease can appear either in childhood or in adults, often making everyday activities challenging and unpredictable.

Table of contents

• What is Still’s disease?
• Types and patterns of the disease
• Symptoms
• What causes Still’s disease?
• Who gets Still’s disease?
• How is Still’s disease diagnosed?
• Possible complications
• Treatment
• Living with Still’s disease

What is Still’s disease?

Still’s disease is a rare type of inflammatory arthritis, which means it causes swelling and pain in the joints along with problems throughout the entire body^[1]. The condition was first described by English physician Sir George Frederic Still in 1896, when he documented it in children^[7].

The disease exists in two main forms. When it begins in childhood, usually between early childhood and late adolescence, it is called systemic juvenile idiopathic arthritis or SJIA. When it starts after age 16, typically in young adults, it is known as adult-onset Still’s disease or AOSD^[3]. Both forms share similar symptoms, including fatigue, fever, joint pain, and inflammation^[4].

adult-onset Still’s disease, AOSD, systemic juvenile idiopathic arthritis, SJIA, systemic-onset juvenile idiopathic arthritis, SO-JIA

Types and patterns of the disease

Still’s disease affects different people in different ways, and it is hard to predict how it will affect any individual. Healthcare providers have observed that symptoms usually occur in one of three patterns^[2]:

• Monophasic pattern: There is only one episode of symptoms that typically lasts weeks to months, but usually less than a year. This form may occur suddenly and go away just as suddenly.
• Polyphasic (or intermittent) pattern: There are multiple episodes of symptoms that occur periodically, weeks, months, or even years apart. These episodes usually get shorter and less severe over time.
• Chronic pattern: Patients have persistent symptoms or regular flare-ups over time. Chronic Still’s disease is more likely to cause progressive damage to joints, similar to rheumatoid arthritis.

Each of these patterns occurs with about equal frequency. Sometimes what appears to be a single episode or intermittent pattern later develops into chronic disease^[2]. For children with SJIA, up to 30% still experience symptoms 10 years after their first symptoms, and symptoms can persist into adulthood^[4].

Symptoms

Most people with Still’s disease have a combination of several symptoms. The primary symptoms include fever, rash, joint pain, and muscle pain^[1].

Fever is one of the most distinctive features of Still’s disease. When symptoms are active, most people have a daily fever that may spike once or twice a day, typically reaching at least 102 degrees Fahrenheit (38.9 degrees Celsius or higher). One spike usually occurs in the morning and another in the evening. These fever patterns may continue for a week or longer^[2].

A distinctive rash usually appears when the fever is spiking. The rash is typically salmon-pink or pinkish in color and usually affects the chest, arms, or legs first, but may spread to other areas. The rash may come and go with the fever, often disappearing between fever spikes^[1].

Joint pain is another major symptom. The joints may feel achy, and many people also experience swelling and stiffness. The knees and wrists are most commonly affected, but the ankles, elbows, hands, and shoulders can also ache. Joint discomfort usually lasts at least two weeks. In some people, inflammation may affect only a few joints at first, but over time more joints may become involved^[1].

Muscle pain usually comes and goes with the fever. The pain can be severe enough to disrupt daily activities^[1].

Other common symptoms include sore throat, which is often one of the first symptoms to appear. The lymph nodes in the neck might be swollen and tender. People may also experience abdominal pain, fatigue, and a general feeling of being unwell (called malaise)^[1].

At first, Still’s disease might feel a lot like a virus or the flu. Symptoms like fever, body aches, and a sore throat resemble many common illnesses. You and your healthcare provider might become more suspicious when your symptoms still have not gone away after two or three weeks^[2].

What causes Still’s disease?

The cause of Still’s disease remains unknown. Inflammation in the body causes the symptoms. Your immune system usually generates inflammation to fight infections and heal injuries, and this is supposed to be a temporary response. But in Still’s disease, the immune system malfunctions and generates inflammation continuously, even when there is no infection to fight^[2].

The prevailing theory suggests that Still’s disease is a reactive condition, meaning that various infectious agents may act as triggers in people with a genetic predisposition. Both genetic factors and various infectious agents, including viruses and bacteria like Yersinia enterocolitica and Mycoplasma pneumoniae, have been proposed as significant contributors^[3]. However, it is uncertain whether these factors are present in all patients with Still’s disease.

Some studies have shown an association between Still’s disease and specific gene types called human leukocyte antigen (HLA) subtypes^[3]. There have also been rare reports of the disease occurring in twins, which suggests a genetic component^[3].

Who gets Still’s disease?

Still’s disease is a very uncommon condition. For the adult form (AOSD), the estimated annual incidence ranges from 0.1 to 0.4 cases per 100,000 people in Europe. For the childhood form (SJIA), recent studies suggest it affects approximately 3.5 per 100,000 children^[4].

The disease affects men and women approximately equally, though some studies suggest that slightly more females are affected than males^[4].

SJIA starts during childhood years, most commonly in the age range of 0 to 5 years^[4]. AOSD typically occurs in younger adults, most often between the ages of 16 and 35. The age distribution follows a bimodal pattern, with the first peak occurring between 15 and 25 years and the second peak between 36 and 46 years^[3].

How is Still’s disease diagnosed?

Still’s disease can be difficult to diagnose because there is no single test that can definitively identify it. Because it is such a rare disease, many doctors will not be familiar with it^[4]. The disease is considered a diagnosis of exclusion, which means doctors must rule out other conditions that have similar symptoms before confirming Still’s disease^[5].

Diagnosis is based on a review of symptoms, medical history, physical examination, and laboratory tests^[6]. No single test identifies Still’s disease. Instead, blood tests are used to rule out other diseases with similar symptoms. Other tests, such as X-rays, may be done to check for joint inflammation or damage^[6].

Imaging tests can reveal damage caused by the disease. Blood tests can help rule out other conditions that have similar symptoms. A distinguishing feature of Still’s disease is a frequently elevated level of a protein called serum ferritin, which often exceeds 1000 ng/ml^[3].

At least seven sets of diagnostic criteria have been created to help identify Still’s disease. The most commonly used are the Yamaguchi criteria, which have the highest sensitivity. According to these criteria, diagnosis requires at least five features, with at least two of these being major criteria. Major criteria include fever of at least 39 degrees Celsius for at least one week, joint pain or arthritis for at least two weeks, a nonpruritic salmon-colored rash, and increased white blood cell count with a predominance of certain immune cells. Minor criteria include sore throat, swollen lymph nodes or spleen, abnormal liver function tests, and negative tests for certain antibodies^[5].

Symptoms of Still’s disease can differ from person to person and can mimic those of other conditions, including lupus and a type of cancer called lymphoma^[1].

Possible complications

People with Still’s disease can develop complications, especially if the condition is not correctly diagnosed and quickly treated^[4].

Possible complications include:

• Joint damage and deformities: Uncontrolled arthritis can result in lasting damage to the joints, particularly the wrists. SJIA, the form that affects children, can be associated with severe arthritis if not sufficiently controlled^[1].
• Enlargement of the liver or spleen: Several of the body’s organs can be affected by the inflammation^[4].
• Macrophage activation syndrome (MAS): This is a severe and life-threatening complication involving excessive activation of immune cells, leading to widespread inflammation, high fevers, organ dysfunction, and a drop in blood cell counts^[4].
• Heart complications: These include pericarditis (inflammation of the sac surrounding the heart), which can lead to chest pain and potential cardiac complications, and myocarditis (inflammation of the heart muscle), potentially resulting in chest pain, irregular heartbeats, and heart failure^[4].
• Lung complications: Pleuritis, or inflammation of the lining around the lungs, can cause chest pain and difficulty breathing. Other serious lung conditions have also been reported^[4].
• Amyloidosis: Rarely, abnormal proteins can deposit in various organs, which can affect their function^[4].

Treatment

A variety of medicines are used to treat Still’s disease. The type of medicine depends on how severe the symptoms are and possible side effects. Medications can help manage symptoms when they arise^[8].

Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin IB) or naproxen sodium (Aleve) may help with mild joint pain and inflammation. Stronger NSAIDs are available by prescription. Since NSAIDs can damage the liver, regular blood tests may be needed to check liver function^[8].

Steroids (also called corticosteroids) such as prednisone are often needed if the disease is severe or does not respond to prescription NSAIDs. Many people who have Still’s disease require treatment with steroids. These powerful drugs reduce inflammation but may lower the body’s resistance to infections and increase the risk of developing osteoporosis and diabetes^[8].

Methotrexate is often used in combination with prednisone. When combined, the prednisone dose can be reduced. Methotrexate is a type of medicine called a disease-modifying drug (DMARD). DMARDs and biologic medicines are needed in more severe cases or if the arthritis becomes chronic^[6].

Biologic response modifiers (also called biologics) may be recommended if other medicines have not worked. These are medicines that block specific proteins causing inflammation. Anakinra (Kineret), canakinumab (Ilaris), and tocilizumab (Actemra) are biologics used to treat Still’s disease. Medications that block the action of a protein called interleukin-1 (IL-1), such as anakinra, can be particularly effective treatments^[8].

With Still’s disease, medications may need to be taken even after symptoms go away. This is called maintenance therapy. It is important to keep inflammation under control to prevent damage to joints and organs^[6]. It may be necessary to take more than one medication at a time to control symptoms^[6].

Living with Still’s disease

Living with Still’s disease requires patience and adaptation. The disease is unpredictable, and people often never know what each day will look like. This can be hard to deal with, especially when having to cancel plans or appointments due to the disease flaring up^[14].

Caring for the body and mind are key components of managing Still’s disease. Making positive and healthy lifestyle choices and acknowledging the physical and emotional effects of the condition are important. Proper nutrition, activity, rest, and following doctors’ orders are essential for managing the condition and possible medication side effects^[6].

Many people find that seeking out support from others who understand their situation helps. Connecting with Still’s disease social media groups and patient organizations can provide hope for the future and help people live better with their condition^[16]. Just speaking with others who understand can be healing^[16].

For some people, Still’s disease has required making major lifestyle changes, including adjustments to their occupation. Finding the right combination of medications that reduces flare-ups can be one of the biggest challenges. Trying different medications to find what works best is often necessary^[14].

Being able to stay active is considered a gift by many people living with Still’s disease. While the diagnosis can trigger a re-evaluation of how active life can be, many people learn to adjust their expectations and what they can reasonably achieve on any given day^[16].