An Overview of Still’s Disease

Still’s disease is a type of inflammatory arthritis that causes fevers, rashes, and inflammation of joints and, sometimes, internal organs. Still’s is also called systemic-onset juvenile idiopathic arthritis (SJIA), as it was first diagnosed in children. SJIA is a type of juvenile idiopathic arthritis (JIA), a group of arthritis conditions affecting children. Still’s disease can also occur in adults and is called adult-onset Still’s disease (AOSD). 

While there is no cure for this debilitating condition, medication and a healthy lifestyle can help with reducing inflammation and managing symptoms.

Prevalence

JIA affects one in 1,000 children and it is estimated that around 300,000 children in the United States have been diagnosed with JIA. SJIA accounts for 10 percent of children with JIA.

Adult-onset Still’s disease is quite rare. It is believed to affect fewer than one in every 100,000 people. It affects men and women equally, and most diagnoses are in young adults ages 16 to 35. The true number of people living with AOSD is unknown because the condition is easily mistaken for other types of inflammatory arthritis due to its rarity and variable symptomology.

Symptoms

Still’s disease causes systemic (whole body) symptoms in both adults and children. The most common symptoms of this condition include:

• Fever: Still’s causes daily fevers of at least 102 degrees Fahrenheit lasting a week or more at a time. Fever spikes tend to occur in the afternoon and early evening and at least once or twice daily, with temperatures returning to normal between fevers.
• Rash: A salmon color rash may accompany fevers. The rash will appear on the trunk, arms, and/or legs. These rashes only last for the length of the fever and will present on different parts of the body with incidences of fever.
• Sore throat: In adults, this is one of the earliest signs of Still’s disease. Both adults and children will experience tender and swollen lymph nodes in the neck.
• Sore joints: Joints can become inflamed and feel painful and stiff.  The knees and wrists are the most commonly affected, but other joints can become inflamed as well.  
• Muscle pain: Muscle pain comes with fevers. Muscle pain can be severe and disrupt the simplest activities of daily living.

Arthritis in Children

Children may also develop arthritis in the spine, jaws, and hip joints. These are areas where SJIA can cause the most destruction and require joint replacement surgeries. The more joints that are affected, the more severe SJIA will be. About a quarter of the children with SJIA will develop chronic polyarthritis (arthritis affecting five or more joints) continuing into adulthood. 

Growth Issues in Children

SJIA can cause growth issues in children. When joints are severely affected, growth may be slowed, especially in the arms and legs. Sometimes, this is the disease itself and, other times, this is related to medications for treating the condition.

Causes

The cause of Still disease is unknown. Some research suggests Still’s may be triggered by ongoing infections, including microbes. Microbes are anything small, such as bacteria, fungi, and yeasts.

Other research suggests Still’s disease is an autoimmune disease. Autoimmune diseases are conditions where the immune system attacks its own healthy tissues.

Neither theory about what may cause Still’s has been confirmed. Suffice to say, no precise cause of Still’s disease is yet known.

When to See a Doctor

It can be difficult to diagnose Still’s disease because it shares certain characteristics with other conditions, including lupus and Lyme disease.

Before making a diagnosis, other medical problems will need to be ruled out. A medical history and physical exam are usually the first steps. Blood work can check inflammation levels, blood cell counts, iron levels, and elevated liver enzymes. Imaging can look for joint damage, inflammation, enlargement of the liver or spleen, and fluid buildup in the lungs and chest cavity.

Treatment

There is no cure for Still’s disease and there is no way to prevent it. Once a diagnosis has been made, the goal is to control symptoms and slow down the disease in order to prevent or lessen complications. 

Early treatment usually involves prevention of inflammation using nonsteroidal anti-inflammatory drugs (NSAIDs), including ibuprofen and naproxen. High-dose aspirin is sometimes used for adult-onset Still's disease but is not recommended in children with SJIA because of the high risk of toxicity, compared to other NSAIDs.

Corticosteroids, such as prednisone, can help when symptoms don’t respond to NSAIDs, but these medications cannot be used for long periods, due to side effects.

For people whose symptoms persist, immunosuppressant drugs are a second-line therapy. These medications affect the inflammatory response of the immune system and include medications such as methotrexate and hydroxychloroquine.

More recently, Still’s disease has been found to involve substances that cause inflammation, including a cytokine protein, interleukin. This knowledge has allowed doctors to start treating Still’s with biologic medications, including biologic injections, such infliximab (Remicade), adalimumab (Humira), and etanercept (Enbrel) and Tocilizumab (Actemra), an intravenous treatment (through a vein using an intravenous drip).

Complications

Potential complications of Still’s disease include:

• Joint destruction due to chronic inflammation
• Inflammation of the heart
• Excess fluid around lungs
• Macrophage activation syndrome (MAS). This disease complication is rare, but could be fatal. MAS may cause low blood cell counts, extremely high triglyceride (type of fat found in the blood) levels, and abnormal liver function.

A Word From Verywell

While there is no cure for Still’s disease, it is treatable and manageable. Treatment can reduce inflammation and other symptoms. Some people may develop chronic arthritis, but medications can help. It is also important to practice a healthy life, which includes a balanced diet, exercise, not smoking, stress management, and getting enough rest.