Arthritis refers to inflammation of the joints, often accompanied by pain, stiffness, or swelling. Arthritis may occur in many different diseases and medical conditions.

Jenny's Story

For many years, Jenny's father was a dedicated runner. He got up early each morning for a three-mile jog, and on weekends he sometimes ran as far as 10 miles or competed in road races. He even talked about training for a marathon, which would mean running more than 26 miles in one race. Gradually Jenny began to hear her father mention that his knees were hurting when he ran, and that they remained painful for a few hours after he stopped. Jenny noticed that his knees looked swollen, and that he sometimes had trouble sleeping because the pain annoyed him so much.

Arthritis affects many different parts of the body, including shoulders, elbows, hands, hips, and knees (left). In healthy joints (top right), a flexible cushion of cartilage allows bones to slide past each other smoothly.

Arthritis affects many different parts of the body, including shoulders, elbows, hands, hips, and knees (left). In healthy joints (top right), a flexible cushion of cartilage allows bones to slide past each other smoothly. But in arthritis (bottom right), cartilage loss forces the bones to touch without their usual cushioning, which creates pain and inflammation.
Illustration by Frank Forney. © 2016 Cengage Learning®.

What Is Arthritis?

Arthritis is a common problem for many older people, but it can affect anyone, from toddlers to centenarians * . Although people use the term as if it were only one disease, arthritis actually refers to a condition found in a large group of disorders. The major symptoms of arthritis occur in and around joints, making them stiff, swollen, and often painful. In addition to the joints, certain types of arthritic diseases may affect other parts of the body, including the heart and lungs.

As a group, the various forms of arthritis are among the most common medical conditions. The Arthritis Foundation estimates that nearly 53 million adults and 300,000 children in the United States have some type of arthritis. It is most common among women and occurs more frequently as people get older. Arthritis usually is chronic, which means the problem can last to some degree for months, years, or the rest of people's lives.

Arthritis affects millions of people. Although there are many types and causes of arthritis, the most common are:

These conditions develop for a variety of reasons, but they are not contagious * . Some forms of arthritis can develop from contagious infections, such as sexually transmitted diseases or viruses that cause mumps and rubella (German measles). Arthritis with severe joint pain and swelling, particularly the knees and other large joints, can develop from untreated Lyme disease (caused by the bite of an infected tick). Sometimes arthritis occurs as one of the symptoms seen in conditions that primarily affect other organs. For example, inflammatory bowel disease may have arthritis as one of its symptoms. One of the most common symptoms of Lupus is arthritis. Fibromyalgia * is considered an arthritis-related condition but is not a form of arthritis. It does not cause inflammation or damage to the joints, muscles, or other tissues. It is considered a rheumatic disease.

What Is Osteoarthritis?

Jenny's father has osteoarthritis, the most common type of arthritis in adults. About 27 million Americans, almost half of those with arthritis, have this kind. Osteoarthritis is sometimes called “wear-and-tear” arthritis. That is because the pain, stiffness, and swelling often result from the wearing down of the protective tissues within and around joints.

More than 150 possible trouble spots

The human body contains more than 150 joints that connect more than 200 bones. Toes and fingers have small joints; the spine, elbows, and knees have larger ones; and the hips and shoulders have even bigger ones. The bones do not touch directly. Instead, a tough, smooth, rubbery layer of tissue called cartilage covers the ends of the bones. When a knee, elbow, or other joint moves, the cartilage allows the bones to slide smoothly past each other. Cartilage is also flexible and absorbs some of the weight placed upon certain joints, such as the knee.

People with osteoarthritis have lost some of the smooth cartilage in their joints. Eventually, the cartilage can wear away so much that the ends of the bones touch without any cushioning. The bones can also grow small spurs or bumps, which is why some people with osteoarthritis have lumps in their joints. These lumps often are most noticeable in the hands.

Those odd pains Stress

No one is exactly sure why osteoarthritis happens, but often it results from stresses placed on the joint. In the example of Jenny's father, his years of running on hard surfaces caused damage to his knee cartilage. The pounding on pavement was too much stress for the cartilage to absorb.

There are other types of stress or injury that can lead to osteoarthritis. People whose jobs involve hard physical labor (such as construction workers) or repetitive tasks (such as assembly-line workers) can develop osteoarthritis. In addition, an injury to a knee or elbow can increase the risk of osteoarthritis. Certain activities such as football or ballet can put a person at greater risk of developing osteoarthritis.

Even the stress of too much body weight contributes to the disease. People who are significantly overweight are more prone to osteoarthritis because their weight places extra stress on joints, especially the knees and hips.


Many older people develop osteoarthritis even if they never put extra stress on their joints. That is because as people age, the rubbery cartilage tissue loses some of its ability to stretch and can become thinner. This change in the tissue places people at greater risk of osteoarthritis.


Not all older people develop osteoarthritis, just as not all runners or laborers do, which is one reason some doctors suspect heredity may play a role in determining who is at greatest risk for this type of arthritis.


It is important to understand what type of arthritis people have because treatments vary. Doctors diagnose osteoarthritis based on the symptoms they see. They might look for loss of cartilage and bone spurs by performing x-rays. Doctors will look for other causes of the pain, for example, blood tests can show that the problem is rheumatoid arthritis rather than osteoarthritis.

If it hurts, why do doctors want patients to exercise?

Once doctors have determined the problem is osteoarthritis, they typically tell patients something that might seem to make little sense. They want their patients to exercise the joint. This advice does not mean Jenny's father should return to running. It does mean that he and others with the disease need to work with their doctors to find the best way to exercise.

Appropriate exercise can strengthen the muscles around the joint and help lessen the stiffness. Often the exercises are different from those done in the past. Some individuals give up running for swimming or water aerobics. Others walk or ride stationary bikes. If the pain is severe, a physical therapist who specializes in helping patients learn appropriate exercises might get involved. If people are overweight, doctors advise them to lose the extra pounds.

X-ray of normal hand and hand with severe rheumatoid arthritis. Bone deformation is seen in finger and hand joints. Most joints are ragged due to bone erosion, with the thumbs also affected.

X-ray of normal hand and hand with severe rheumatoid arthritis. Bone deformation is seen in finger and hand joints. Most joints are ragged due to bone erosion, with the thumbs also affected. People with rheumatoid arthritis may feel stiffness when they wake up in the morning, and their joints may feel warm to the touch.
Alila Medical Media/
Treating the pain

The pain of arthritis is often treated with aspirin or other over-the-counter drugs that reduce swelling. In addition, stronger prescription drugs can help if the pain is extreme. In some cases, doctors may recommend that corticosteroids * or artificial joint fluid, known as hyaluronic acid derivatives, be injected into the joints.

Often the pain of osteoarthritis decreases with treatment. For some people, surgery is performed to remove stray pieces of damaged cartilage, to smooth bone spurs, or in severe cases to replace damaged joints with mechanical ones. Hips and knees are the most likely candidates for replacement.

What Is Rheumatoid Arthritis?

The ancient Greeks believed the human body is filled with various substances they called “humors.” They said the humors sometimes got out of balance and caused illnesses, such as the aches and pains of swollen joints. The humors, they believed, could get back in balance, and the pain would subside. But the problems also could return. One disease the Greeks observed is what was later called rheumatoid (ROO-ma-toid) arthritis. Rheuma derives from a Greek word that means “flux” or “discharge.” The Greeks believed the humors were fluxing, or flowing, through the body to cause the bouts of pain.

When the body turns on itself

In a way, rheumatoid arthritis is a disease in which substances in the body are out of balance. The body fights infections with chemicals known as antibodies. In rheumatoid arthritis, the antibodies turn against healthy areas of the body and cause the thin covering around joints to become inflamed.

* .

Approximately 2 million Americans have rheumatoid arthritis, and most of them are women. Although it is primarily a disease that begins at middle age, its onset may be much earlier.

Known as the most disabling of the various diseases that cause arthritis, rheumatoid arthritis can lead to deformed joints, extreme pain, and loss of the ability to do common tasks such as walking.


Rheumatism is a nonmedical word that many people use to refer to many different forms of arthritis, including rheumatoid arthritis. Older men and women sometimes talk about “having a touch of rheumatism” when their joints ache, especially on cold, rainy days.

Stiffness in the morning

The symptoms of the disease can develop in a few days, or over months or years. For most people, joints in the hands, feet, arms, or legs feel stiff, as they do in osteoarthritis and other forms of arthritis. Rheumatoid arthritis has different distinctive features, however. People tend to feel worse in the morning after awakening. They can also get a fever, and their joints can seem warm to the touch.

At first, the antibodies attack only the thin covering around joints. This covering contains cells that produce fluid to keep joints lubricated and working properly. As the covering is injured, it becomes thicker. Soon, damaging cells appear and eat away cartilage, bone, and other tissue. Swelling and pain result, and the joints become deformed. People with rheumatoid arthritis can develop small bumps around joints, especially in their hands and elbows. Often, the disease flares up and then subsides on its own. Some people receive no relief without treatment.


Doctors diagnose rheumatoid arthritis with special blood tests. They look for other causes of the joint problems and use x-rays to look at the spaces between bones to see whether they are narrowing.


Over-the-counter medications such as aspirin, ibuprofen, or acetaminophen can ease the pain. Stronger prescription pain relievers and anti-inflammatory drugs are available. Weight loss is urged for people who are too heavy. Some people need surgery to replace badly damaged joints in the arms, legs, or hips. Many people learn to live with the disease through a combination of rest and exercise. When the symptoms are at their worst, patients with rheumatoid arthritis should try to avoid putting stress on their joints to help reduce damage. When the symptoms are less severe, doctors want the patients to exercise as a way of maintaining flexibility in the joints and strength in the muscles around them. Patients with rheumatoid arthritis often learn relaxation techniques, because the disease is known to flare up in times of emotional stress.

What Is Juvenile Rheumatoid Arthritis?


Juvenile rheumatoid arthritis affects children under the age of 16 years. Although it is similar to the adult form of rheumatoid arthritis, which is chronic, some young patients “outgrow” juvenile rheumatoid arthritis. Doctors use a similar approach to juvenile and adult rheumatoid arthritis: pain medication, exercise recommendations, and careful treatment to prevent joints from becoming deformed.

What Are the Other Forms and Causes of Arthritis?

Osteoarthritis is the most common form of arthritis, and rheumatoid arthritis is the most disabling, but more than 100 diseases are accompanied by the symptoms of arthritis.


Gout causes extreme pain that develops suddenly, often in the big toe. The pain, swelling, and redness develop because uric acid crystals build up in the joint. A natural substance found in the body, uric acid usually passes out of the system through the kidneys in the urine * . When uric acid is not removed from the body, crystals form and settle in the joints. Many people associate gout with excessive eating and drinking. Although those activities, as well as obesity * , increase the risk of gout, it can develop for no apparent reason. According to the Arthritis Foundation, gout occurs in about 4 percent of all Americans, the majority being men.


Lupus is a disease that affects joints as well as other body parts, such as the kidneys, nervous system, heart, and skin. Lupus has many symptoms, including fatigue, rashes, chest pain, fever, and sensitivity to sunlight. Like rheumatoid arthritis, lupus is an autoimmune disease with no known cause. In autoimmune diseases, the cells in the body that usually fight infections instead attack healthy cells and tissue. According to the Lupus Foundation of America, this disease affects 1.5 million Americans, 90 percent of whom are women in their childbearing years. People of color, including African Americans, Asians, Hispanics, and Native Americans, are two to three times more likely to develop lupus than are women of European ancestry.

Lyme disease

Lyme disease is a bacterial infection spread by the bite of an infected insect known as a deer tick or black-legged tick. The first signs are usually fever and a red rash on the skin where the bite occurred, although early symptoms are sometimes overlooked. Joint problems may follow, but may not appear until months to years later. If caught early, the disease usually can be overcome with antibiotics. Lyme disease is a special concern for people who spend time outdoors throughout the United States and in more than 60 other countries.

Living with Arthritis

Severe arthritis can limit a person's ability to walk, dress, or bathe easily. A growing number of devices are designed to help people with varying forms of arthritis perform simple tasks more easily and to continue living independently. These range from easy-to-open bottles and gripping clamps on poles for reaching high objects to electric scooters.

Although doctors do not yet know how to prevent arthritis, they typically recommend ways people can reduce its impact. These include:

With a fuller understanding of arthritis, its limitations, and its treatments, people with arthritis can lead full and happy lives.

See also Arthritis, Infectious • Autoimmune Disorders: Overview • Collagen Vascular Diseases: Overview • Fibromyalgia • Gout • Lupus • Lyme Disease • Raynaud's Disease


Books and Articles

Shlotzhauer, Tammi L. Living with Rheumatoid Arthritis. Baltimore: Johns Hopkins University Press, 2014.


American College of Rheumatology. “Rheumatoid Arthritis.” (accessed March 10, 2016).

MedlinePlus. “Arthritis.” U.S. National Library of Medicine, National Institutes of Health. (accessed March 10, 2016).


American Academy of Orthopaedic Surgeons. 9400 W. Higgins Rd., Rosemont, IL 60018. Telephone: 847-823-7186. Website: (accessed March 10, 2016).

Arthritis Foundation. 1330 W. Peachtree St., Suite 100, Atlanta, GA 30309. Phone: 404-872-7100. Website: (accessed March 10, 2016).

* centenarians are people who are at least 100 years old.

* osteoarthritis (os-tee-o-ar-THRYtis) is a common disease that involves inflammation and pain in the joints (places where bones meet), especially those in the knees, hips, and lower back of older people.

* rheumatoid arthritis (ROO-mahtoyd- ar-THRY-tis) is a chronic disease characterized by painful swelling, stiffness, and deformity of the joints.

* juvenile rheumatoid arthritis is a joint disease in children with symptoms of high fever, rash, swollen lymph glands, enlarged spleen and liver, and inflammation around the heart and of the lungs. Arthritis in the joints appears later. This disease is also known as systemic-onset chronic arthritis or Still's disease.

* gout occurs when deposits of uric acid in the joints cause inflammation and pain.

* lupus (LOO-pus) is a chronic, or long-lasting, disease that causes inflammation of connective tissue, the material that holds together the various structures of the body.

* Lyme disease (LIME) is a bacterial infection that is spread to humans by the bite of an infected tick. It begins with a distinctive rash and/or flu-like symptoms and, in some cases, can progress to a more serious disease with complications affecting other body organs.

* contagious (kon-TAY-jus) means transmittable from one person to another, usually referring to an infection.

* fibromyalgia (fi-bro-my-AL-ja) is a group of disorders that are characterized by achy, tender, and stiff muscles

* corticosteroids (kor-tih-ko-STIRoyds) are chemical substances made by the adrenal glands that have several functions in the body, including maintaining blood pressure during stress and controlling inflammation. They can also be given to people as medication to treat certain illnesses.

* Raynaud's disease (ray-NOZE) is a condition in which discoloration of the skin typically on the fingers and/or toes occurs when individuals experience changes in temperature or emotional events. An abnormal spasm of blood vessels causes the reduced supply of blood to the affected areas of the body.

* urine is the liquid waste material secreted by the kidneys and removed from the body through the urinary tract.

* obesity (o-BEE-si-tee) is an excess of body fat. People are considered obese if they weigh more than 30 percent above what is healthy for their height.

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

(MLA 8th Edition)