Arthritis is pain and stiffness in the body, usually in the joints. The joints are where bones meet, such as at the hips, knees, or elbows. There are several kinds of arthritis; the most common are osteoarthritis, rheumatoid arthritis, and juvenile arthritis.


Arthritis is a common cause of disability because it limits joint movement. The body's skeleton is made up of different types of strong, fibrous connective tissues. Bone, cartilage, ligaments, and tendons are forms of connective tissue that have different makeups and characteristics. The joints that hold bones together and help people make movements are complex areas made up of these various tissues, fluids, and two or more bones. Osteoarthritis, also known as degenerative joint disease, usually affects people older than age 50, because it is a gradual loss of the cartilage that protects joints. People with osteoarthritis develop bony spurs and cysts at their joint margins that cause pain and inflammation.

Although rheumatoid arthritis also causes pain, swelling, and even deformity of joints, it actually is a disease of the immune system. The chronic, or ongoing, disease can cause inflammation and other problems throughout the body. For example, some people with rheumatoid arthritis develop weak bones (osteoporosis). When someone has rheumatoid arthritis, the cells of the immune system attack the synovial membrane that lines the inside of certain joints, and it becomes inflamed. This membrane normally supplies synovial fluid that lines the empty space, or cavity, between the bones. The fluid lubricates the joint so that bones move smoothly. When the membrane becomes inflamed, it thickens and stiffens, making movement difficult. White blood cells can invade the membrane, eventually attacking and destroying cartilage along the joint's bony surfaces and causing ligaments to wear away.

Juvenile arthritis has several types but typically involves swelling, heat, and pain in the joints. It occurs in children under age 16 and can last throughout their lifetime. The child's immune system attacks the synovia, the tissues that line the joints. When the synovia inflame, this causes the swelling, pain, and stiffness that makes movement difficult.


According to the Centers for Disease Control and Prevention, arthritis limits the activities of more than 22 million adults in America, and more than 52 million adults report that a physician has diagnosed them with arthritis. That means that more than 22% of American adults have some form of arthritis. The number of people who have arthritis increases with age. Slightly more women than men have arthritis. It also increases as body weight increases: About 16% of adults who are underweight or at normal weight report having arthritis, but nearly 23% of overweight adults and 31% of adults who are obese report that they have arthritis. About 294,000 children under age 18 in America have some form of arthritis. Juvenile arthritis affects about 300,000 children in the United States.

Causes and Symptoms

Arthritis may have various causes, but the symptoms are similar, although the pain may vary in severity.

Rheumatoid arthritis

Physicians still do not know exactly what causes rheumatoid arthritis. Researchers have identified some genes involved, but the genes do not fully explain why some people develop the disease. For instance, something must set off the immune system and trigger the disease. This is known as an environmental factor. Scientists have researched the possibility that an infection leads to rheumatoid arthritis. Female hormones could be involved because nearly 70% of people with this form of arthritis are women. Smoking might be another factor, because it seems to increase the likelihood that people who have the genetic factor that leads to rheumatoid arthritis will develop the disease.

Symptoms can develop gradually or strike quickly. People usually experience pain, swelling, and stiffness in their joints. Rheumatoid arthritis most often affects the hands, feet, wrists, elbows, and ankles, but can occur in other joints as well. It affects joints symmetrically, meaning that if the right wrist is affected, the left wrist also will be affected. Pain usually is worse in the morning. Over time, the joints of people with rheumatoid arthritis can become deformed.


Osteoarthritis is the most common form of arthritis. It occurs because the cartilage that protects and cushions bones in joints begins to deteriorate or disappear. It usually occurs in weight-bearing joints, such as the hips and knees. Bone spurs and pockets of fluid form, causing pain in the joints. Pain begins as mild morning stiffness, but becomes worse over time to the point where the patient might experience pain even when the joint is not used.

There are two types of osteoarthritis: primary and secondary. In primary osteoarthritis, which usually strikes older adults, the problems come from normal weight bearing and use. Secondary osteoarthritis results from chronic or sudden injury to a joint and can occur in any joint. Often, it can occur about 10 years after a sports injury to a joint, or it may result from repeated strain to a joint from an occupation or from being overweight. Joints become stiff and painful upon waking and during or after use. The joint may also stiffen after not being used for a period of time. Research uncovered possible roles in the cells that can add to development of osteoarthritis, including one that affects inflammation.

Juvenile arthritis


Several tests, along with symptoms, physical examination, and medical history, are used to diagnose arthritis. Nearly every patient who has rheumatoid arthritis has low levels of red blood cells, or anemia. Nearly 80% of those diagnosed also have a blood protein related to arthritis. Blood tests also can identify high erythrocyte sedimentation rates, which confirms the joints are inflamed. The physician might order x-rays or magnetic resonance imaging (MRI) of the joint. Osteoarthritis usually is diagnosed with a combination of patient history, physical examination, and medical imaging. MRI often is used to closely study the joints and tissues. A diagnosis of juvenile arthritis is made mostly through a complete medical examination and laboratory tests to rule out other causes of symptoms. Children with juvenile arthritis also might have high levels of a blood protein related to the disease.


Treatment varies, depending on the type of arthritis and severity, but most arthritis is treated with a combination of medication, physical therapy, and surgery in more severe or painful cases. The surgery may involve repairing or replacing an affected joint. Treatment also might involve changes in activity and weight loss to ease the load on weight-bearing joints, or other recommendations to improve joint function. Treatment is designed for each individual patient as much as possible.

Rheumatoid arthritis

Certain medications, such as nonsteroidal anti-inflammatory drugs and steroids, can help decrease pain and swelling in joints when symptoms are less severe. Medications called disease-modifying antirheumatic drugs (DMARDs) work by slowly trying to change the course of the disease and easing symptoms. The DMARD used most is methotrexate. Drugs called biologic agents can target parts of the immune system and block inflammation of arthritic joints. Examples of biologic agents are abatacept and rituximab. Research continues on therapies that can target specific cell actions and other functions to improve management of arthritis and lessen side effects from drugs.

Tissue that is elastic and connective. It covers and protects the ends of joint bones.
Subchondral cysts—
Fluid-filled sacs that form inside the joints in people who have osteoarthritis.
Synovial joint—
A type of joint that allows articular movement, or movement in many directions.

People with arthritis may find physical activity uncomfortable, but studies have shown that activity is key to decreasing pain. Walking or performing a similar weight-bearing activity at least 30 minutes each day improves pain, function, mood, and quality of life. The activity should be moderate in intensity and low impact. Other examples of suggested activities are swimming, cycling outdoors, and using elliptical bicycles. The Arthritis Foundation recommends making exercise a part of patients' daily routines and suggests that if pain or being overweight keeps people with arthritis from exercising, they should try the foundation's programs that ease stress applied to joints. Physicians also recommend stretching exercises to keep joints loose and working with a team of caregivers to learn to cope with rheumatoid arthritis.


Treatment for osteoarthritis varies depending on the joints affected, severity, and cause of the arthritis. Analgesics such as acetaminophen can help, and corticosteroids can ease inflammation in more severe cases. Topical analgesics are creams or salves that can be rubbed onto the affected joint to help relieve pain. Some patients might receive steroid injections or acid therapy in the joints. Other patients might need surgery to relieve severe pain or improve the joint's movement or alignment. The surgery might repair or replace the affected joint.

As with rheumatoid arthritis, physical activity can decrease pain from osteoarthritis. Walking, swimming, cycling outdoors, and using elliptical bicycles at least 30 minutes each day improves pain, function, mood, and quality of life. The activity should be moderate in intensity and low impact. Physicians also recommend stretching exercises to keep joints loose; yoga often is recommended. Physical activity offers another important benefit. It can help people with osteoarthritis lose weight. Each extra pound of weight puts the equivalent of four pounds of pressure on the knees, so weight loss is important.

Juvenile arthritis

Treating juvenile rheumatoid arthritis involves trying to control inflammation and pain, and minimize the damage the disease can cause to children's joints. Physicians also help patients maintain their joint functions as much as possible. Doctors try to classify the type and severity of disease to plan treatment. Many of the same over-the-counter pain relievers and prescription anti-inflammatory drugs are used, along with a DMARD (also called a slow-acting antirheumatic drug), such as hydroxycholoroquine. The drugs help control pain and swelling in joints, and sulfasalazine helps with joint pain, stiffness, and swelling. Other medications may help improve immune system function or block the proteins that cause inflammation.

Exercise is important for children with arthritis. Therapists work with children to perform exercises to keep range of motion in their joints, and children are taught how to perform these at home. Participating in sports and other physical recreation can help keep children's joints and muscles exercised and strong, and assist them in developing confidence in their physical abilities. The best exercises are those, such as swimming, that do not stress the joints too much or risk injury.


A small percentage of patients with rheumatoid arthritis have symptoms for a brief period of time and then get better. Others go into remission, during which symptoms ease even though their joints remain inflamed. For most people with the condition, however, it is a long-term and chronic medical problem. Several factors make prognosis worse, such as having more joints affected, having high levels of certain blood markers, or being older at diagnosis. People with rheumatoid arthritis usually have shorter life spans. Some children with juvenile arthritis outgrow the disease and stop needing treatment, but many need long-term medication and other care.

No cure has been found for osteoarthritis, and the condition usually continues to worsen. If a person is overweight, losing weight can make prognosis better, as can maintaining regular exercise as prescribed. If people with osteoarthritis become inactive because of pain and fail to treat the problems with their joints, they may gain more weight and find their health worsens because of other conditions affected by being overweight and inactive, such as diabetes and heart disease.

It is difficult to predict the course and outcome of juvenile arthritis. Many children have the disease in more than one joint, but most can continue to move and function normally as adults. They will require ongoing care for the rest of their lives. Blood markers help physicians predict how severe the disease will be.



There is no known way to prevent rheumatoid or juvenile arthritis, though researchers continue to look into genetic solutions and ways to control immune system responses. The most patients can hope to do is prevent or slow the disease's progress. There is a genetic connection to some types of osteoarthritis. Still, people at risk can prevent or delay some forms by maintaining a healthy weight or losing weight by eating right and exercising regularly, especially using aerobic exercise. It is important to seek treatment immediately for injured joints.



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Arthritis Foundation, 1355 Peachtree St NE, Suite 600, Atlanta, GA, 30309, (404) 872-7100, (844) 571-4357, .

Teresa G. Odle, BA, ELS

  This information is not a tool for self-diagnosis or a substitute for professional care.