Juvenile idiopathic arthritis (JIA) is a type ofinflammatory arthritisthat starts in children under 16. It was previously known as juvenile rheumatoid arthritis.

Most forms of JIA are due to an immune system malfunction. While the exact cause of this自动免疫问题is unknown, the malfunction provokes a child’s immune system to attack their joint linings, causing inflammation and — if left untreated — joint damage.

This form of juvenile arthritis can involve one or more joints and can occasionally affect the eyes. To fall under the juvenile idiopathic arthritis heading, symptoms must persist for more than 6 months.

Current research suggests that there may be many different subtypes of JIA with slight clinical differences, but the most common types of juvenile arthritis are the following:

  • Oligoarthritis.This type typically affects four or fewer joints in the first 6 months of onset. The most often affected joints are the larger ones such as knees, ankles, and elbows. People with this type of juvenile arthritis are at a greater risk of developing inflammation in the eyes. This specific type of inflammation, known asuveitis和iritis, can sometimes persist after the oligoarthritis has subsided.
  • Polyarthritis.Also called polyarticular JIA, this type involves more of the body than oligoarthritis. It affects five or more joints in the first 6 months of illness, often on both sides of the body.
  • Systemic JIA.This type can cause inflammation in one or more joints, askin rash, and in some cases, enlargement of the liver, lymph nodes, or spleen. A fever that lasts for 2 or more weeks before or after the onset of the disease is also common.
  • 银屑病的贾。This type occurs whenpsoriasisis present alongside other symptoms such asnail pitting, nail separation (甲脱离), and the swelling of a single whole finger or toe (腺炎).
  • Enthesitis-relatedJIA.这种类型涉及一种压痛，骨骼与关节炎炎症一起遇到韧带或肌腱。受影响的最常见区域是臀部，膝盖和脚。
  • Undifferentiated arthritis.This type doesn’t fit within any other subtype. Symptoms can span two or more of the subtypes.

The symptoms of arthritis can come and go in waves, called flare-ups. During a flare-up, symptoms worsen. Symptoms go into remission — become less severe or disappear — between flare-ups.

JIA manifests differently in everyone. A child may have a few flare-ups and then never have symptoms again. They may also experience frequent flare-ups or flare-ups that never go away.

While certain types of juvenile arthritis have their own specific symptoms, there are some commonplace symptoms that can show up throughout all types.

Joint pain and loss of mobility

The most common symptom of JIA isjoint pain. Joints may swell and grow tender. They can turn red and feelwarm to the touch或变得僵硬并失去流动性。这可能导致敏捷性丧失，尤其是在手中。

If JIA is left untreated, children may find themselves becoming less physically active due to pain and loss of mobility. If JIA continues for a long time without treatment, joints may become permanently damaged.

Fatigue

The joint pain from arthritis can disrupt sleep.Chronic inflammationcan also cause persistentfatigue.

Loss of appetite

Loss of appetite, either due to fatigue and pain or other symptoms, is also common in young children with JIA.

Uneven growth

Persistent arthritis at a young age can damage joints. Depending on the joints involved in the type of JIA a child is living with, bones near those inflamed joints may grow more quickly than they’re naturally supposed to, causing limbs to be uneven.

Severe juvenile arthritis can also slow overall growth. However, when the inflammation is controlled, growth issues typically improve.

Eye problems

与JIA有关的常见眼睛问题是blurry visionor dry, “gritty” feeling eyes.

某些类型的JIA，例如少突性炎，可能导致炎症性眼部问题，例如葡萄膜炎和肠炎。尽管慢性葡萄膜炎并不总是引起症状，但突然发作的急性前葡萄膜炎会导致眼睛疼痛，发红和对光的敏感性。

These symptoms should be treated right away, as they can cause long term damage to vision and the eyes themselves.

Fever and skin rash

Inflammation can cause rashes and fevers on its own, but different forms of juvenile arthritis can also cause specific rashes.

Children living with systemic JIA may experience a high fever and a light pink rash on their skin. The rash most commonly appears on these body parts:

  • chest
  • 腹部
  • back
  • 手
  • feet

The rash and the fever appear together and can come and go very suddenly. A fever from JIA can spike above 103°F (39.4°C) and can last for weeks.

Psoriasis, a red, itchy rash, can also present along with psoriatic juvenile idiopathic arthritis.

Swollen lymph nodes and internal organs

Systemic JIA can cause lymph nodes, which are small glands that act as your body’s filters,to swell up and become inflamed. Lymph nodes are found all over the body, including the corners of the jaw, in the armpits, and inside the thighs.

Sometimes swelling can spread to the internal organs, affecting the heart, liver, spleen, and the tissue that surrounds the organs (serositis). In rare cases, the lungs can become inflamed. A rare, but serious, complication called macrophage activation syndrome (MAS) can occur when the immune system goes into extreme overdrive.

If juvenile idiopathic arthritis is left unchecked and untreated, it can cause severe symptoms, including:

  • difficulty chewing or brushing teeth
  • digestive issues
  • inflammation of the cervical spine
  • bone and cartilage damage
  • osteoporosis
  • lung disease
  • damage to the heart
  • 视力问题
  • late onset puberty

A juvenile arthritis diagnosis can create a lot of uncertainty, for both a child and their parents.

It can also be a challenging, painful condition to live with. However, with proper treatment and symptom management, most young people with juvenile idiopathic arthritis live completely normal lives. In certain cases, JIA can even go into remission as a child grows into an adult.

If you or someone you know has been dealing with one or more of these symptoms, the first step is contacting your doctor. The faster you get a diagnosis, the faster you can find relief and long-term management of symptoms.