Arthritis is the leading cause of disability in the United States. The condition causes joint pain and stiffness that can sometimes make it difficult to lead an active life. It usually affects older adults, although some forms of arthritis can occur in younger people, including children. Arthritis isn’t reversible, but treatment can help slow the progression of the disease, minimize discomfort, and support joint health.
Learn about arthritis, why it occurs, and the symptoms it may cause, as well as treatment options that can help you manage the condition and stay on the move.
What is arthritis?
Arthritis is an umbrella term for more than 100 types of degenerative joint diseases, or diseases that impact joints and surrounding connective tissues and tend to get worse over time. According to the Centers for Disease Control and Prevention (CDC), arthritis affects around 58.5 million adults in the U.S., or about one in every four adults.
Arthritis is characterized by pain, stiffness, and swelling in one or more joints. (Joints are places in the body where two or more bones connect and come into contact.) Different types of arthritis can impact joints differently and cause various symptoms, but most people with arthritis experience joint pain and reduced mobility.
What are the different types of arthritis?
Osteoarthritis (OA) and rheumatoid arthritis (RA) are the two most prevalent types of arthritis. Other common types include psoriatic arthritis (PsA), gout, ankylosing spondylitis (AS), juvenile idiopathic arthritis (JIA), and reactive arthritis.
Osteoarthritis is the most common type of arthritis by far. It affects more than 32.5 million adults in the U.S., according to the CDC.
OA occurs when the cartilage in a joint begins to break down and wear away. Cartilage is a tough but flexible connective tissue that helps protect and cushion the ends of bones that come together in a joint. When healthy, cartilage promotes smooth, comfortable movement within a joint.
As OA gets progressively worse, cartilage may break down completely and cause bones to touch and rub together, which can lead to severe pain and stiffness. OA most often occurs in the knees, hips, hands, and spine, although it can affect many joints throughout the body.
Rheumatoid arthritis (RA)
Rheumatoid arthritis is an autoimmune disease. This means the body’s immune system (which ordinarily protects against threats like bacteria and viruses that may cause the body harm) mistakenly attacks healthy joint tissues instead. This immune response triggers inflammation in the lining of a joint capsule—the sturdy membrane that encloses and protects the joint. The result is painful swelling that may lead to permanent joint damage over time.
RA most often occurs in the hands, wrists, and knees and can affect several joints at once. It’s considered a systemic condition, meaning it can impact structures throughout the body, including organs.
Psoriatic arthritis (PsA)
Another type of inflammatory autoimmune disease that affects the joints is psoriatic arthritis. It typically occurs in people who have psoriasis, a condition in which new skin cells grow too quickly and form scaly patches on the skin. About one in three people with psoriasis will develop PsA.
This arthritis type causes joint inflammation that can present in many ways, including tenderness, warmth, or swelling in the fingers, hands, wrists, ankles, or knees. In other cases, the feet, buttocks, or low back can be affected. Having psoriatic arthritis may also increase your risk of gout.
Gout is a type of inflammatory arthritis that results from a buildup of uric acid in the body. Uric acid is a waste product that forms when the body breaks down purines. These are natural substances found in the body’s cells as well as in certain foods and drinks such as anchovies, mackerel, organ meats, beef, bacon, bison, venison, dried beans and peas, and beer. The buildup of uric acid can cause uric acid crystals to lodge in joints and trigger inflammation.
Gout typically affects one joint at a time (often the big toe) and may be very painful. Symptoms usually come on suddenly in flares that can last days or weeks.
Ankylosing spondylitis (AS)
Spondyloarthritis is an umbrella term that describes inflammatory diseases that affect spinal joints. Ankylosing spondylitis, the most common type of spondyloarthritis, causes inflammation in spinal joints and ligaments that can progress to impact the knees, hips, or ankles. A person with ankylosing spondylitis may have back pain and stiffness that comes and goes or is ongoing. Unlike several other types of arthritis, ankylosing spondylitis often occurs in people younger than age 45.
Juvenile idiopathic arthritis
Arthritis can sometimes affect children. The most common type of childhood (juvenile) arthritis is juvenile idiopathic arthritis, which was formerly known as juvenile rheumatoid arthritis. It affects roughly one in every 1,000 children under the age of 16, according to the American College of Rheumatology.
Like rheumatoid arthritis in adults, JIA triggers inflammation that can cause joint pain, swelling, and stiffness. It can also affect other parts of the body, including the liver and eyes. Many children and teens outgrow JIA, but it may last through adulthood in some cases.
As its name suggests, reactive arthritis is an inflammatory reaction to a bacterial infection. Arthritis symptoms usually occur a few weeks after the infection in the digestive tract, urinary tract, or genitals has cleared. The hallmark signs of reactive arthritis are inflammation that develops in the joints, eyes, or urinary tract. It usually resolves on its own in a few weeks or months, but in some cases, it may become chronic (lifelong).
What are the signs and symptoms of arthritis?
Arthritis symptoms vary based on which type you have, how advanced the disease is, what joints are affected, and individual factors such as your age and health.
Osteoarthritis symptoms tend to progress slowly. The most common symptoms of OA include:
- Pain or aching during physical activity, after an extended period of activity, or at the end of the day
- Popping or clicking sounds when bending the joint
- Joint stiffness that may be worse after waking up in the morning or following periods of rest
- Joint swelling
- Stiffness that may improve after physical activity
- Muscle weakness around the joint
- Joint instability or buckling
- A scraping or grating sensation within the joint (usually one or both knees)
In its early stages, OA may not cause any noticeable symptoms. When symptoms do occur, their severity can range from mild to debilitating. Keeping an osteoarthritis symptom journal may help you better track your symptoms and understand what triggers them.
Rheumatoid arthritis symptoms
The first signs of rheumatoid arthritis are usually joint pain and tenderness. As the condition progresses, symptoms may involve:
- Pain, tenderness, and swelling that persists for more than six weeks and often affects multiple joints at the same time
- Pain in small joints, such as the fingers, wrists, and feet
- Joint stiffness in the morning that lasts for 30 minutes or more
- Fatigue, fever, weight loss, or weakness
The symptoms of rheumatoid arthritis tend to occur on both sides of the body. RA flare-ups or flares (periods of worsening symptoms) can happen and last for several weeks or months. In between flares, remission from RA (periods of few or no symptoms) may occur.
Psoriatic arthritis symptoms
In addition to psoriasis, which can cause scaly patches of skin that may appear red or silver, symptoms of psoriatic arthritis can include:
- Joints that are tender, swollen, or warm to the touch on one or both sides of the body
- Noticeably swollen fingers or toes
- Foot pain
- Low back pain
- Changes in nail texture and appearance, including nails that crumble or separate from nail beds
- Eye pain, redness, or blurred vision (which may indicate an inflammatory condition called uveitis)
As with rheumatoid arthritis, psoriatic arthritis remission periods may follow flare-ups.
Gout flares—sometimes called gout attacks—occur suddenly and usually peak after 12 to 24 hours. These flares tend to affect one joint at a time and may involve:
- Intense joint pain, often in the big toe
- Joint swelling and redness or discoloration
- A joint that’s warm to the touch
Gout usually develops in a toe, ankle, or knee. A gout flare may last a few days or weeks and is followed by a period of remission that can last for weeks, months, or even several years. It’s possible to experience just one gout attack in your lifetime. In severe cases of gout, tophi (hard lumps of uric acid crystals) can form on bones or tissues around joints.
Ankylosing spondylitis symptoms
The main symptom of ankylosing spondylitis is low back pain that may be constant or come and go. As the disease progresses, other parts of the body can be affected. Possible symptoms of ankylosing spondylitis include:
- Joint pain that worsens after periods of inactivity and improves with movement
- Pain, swelling, or stiffness in the shoulders, ribs, hips, knees, or feet
- Soreness when taking deep breaths (if rib joints are affected)
- Irritable bowel syndrome
- Depression and other mental health issues
- Eye pain and changes in vision
Juvenile idiopathic arthritis symptoms
The symptoms of juvenile idiopathic arthritis will vary depending on its type (JIA has six different subtypes). Generally speaking, a child with arthritis may experience:
- Joint pain or stiffness that may worsen after periods of inactivity
- Joints that are tender, red, discolored, or warm to the touch
- Skin changes that may include scaly patches, reddish or discolored rashes, or small bumps or nodules
- High fever
- Eye pain, redness, or blurred vision
- Growth issues, such as delayed growth or one arm or leg that’s longer than the other
JIA symptoms may come in flares or feel constant. It can affect any part of the body, including the spine, elbows, hips, knees, ankles, fingers, or toes.
Reactive arthritis symptoms
For many people with reactive arthritis, symptoms involve a combination of:
- Painful, red, discolored, or swollen joints, often in the knee, ankle, or lower back
- Increased urinary urgency or a burning sensation while urinating
- Eye redness, pain, burning, itching, blurred vision, or discharge that may form a crust overnight
- Weight loss
- Abdominal pain or diarrhea
- Small mouth ulcers
The symptoms of reactive arthritis can range from mild to debilitating. They typically occur suddenly, usually between one and six weeks after the initial bacterial infection has cleared.
What causes arthritis?
The exact cause of arthritis is unknown in some cases. Generally speaking, someone could develop arthritis if they:
- Have a family history of arthritis
- Develop certain infections or autoimmune diseases
- Frequently engage in activities that place strain on their joints
The specific causes of arthritis vary by type:
- Osteoarthritis: OA is caused by years of wear and tear on joint cartilage, which can be accelerated by joint injuries or infections.
- Rheumatoid arthritis: RA is an autoimmune disease that causes the immune system to mistakenly target healthy joint tissue and trigger inflammation. Experts aren’t certain what causes RA, but genetics, stress, and viral or bacterial infections could play a role.
- Psoriatic arthritis: PsA is an autoimmune disease that’s connected to psoriasis. Like RA, the exact cause of psoriatic arthritis is unclear, although genetic and environmental factors are thought to contribute to this condition.
- Gout: A buildup of uric acid can lead to gout. Several factors can cause this buildup, including genetics, underlying health concerns like high blood pressure and psoriasis, and a diet high in purines.
- Ankylosing spondylitis: AS can have a genetic basis—meaning it may run in families—but the cause of this type of arthritis isn’t always clear.
- Juvenile idiopathic arthritis: The precise cause of JIA is unknown, although a combination of genetic and environmental factors is believed to play a role in its development.
- Reactive arthritis: Reactive arthritis is triggered by a bacterial infection, although it’s considered to be a separate condition from the infection. The types of bacteria most closely associated with reactive arthritis are campylobacter, shigella, chlamydia, salmonella, and yersinia.
What are the risk factors for arthritis?
A risk factor is a behavior, personal characteristic, or environmental influence that increases your risk of developing a certain condition. Risk factors for arthritis also vary by type, but some general factors that may leave you more susceptible to arthritis include:
- Age: The risk of rheumatoid arthritis and osteoarthritis increases with age. In fact, more than 80 percent of people over age 55 have some X-ray evidence of osteoarthritis.
- Weight: People who are overweight or obese are more likely to develop osteoarthritis in their knees, hips, or spine than people who are at a healthy weight. Gaining too much weight can also make an existing case of arthritis worse.
- Joint injury: Injuring or frequently putting strain on a joint (think squatting with weights, lifting objects overhead, or sprinting) can increase your likelihood of osteoarthritis.
- Smoking: Smoking cigarettes raises your risk of rheumatoid arthritis and many other health problems.
- Infection: It’s possible for bacteria or viruses to infect joints and contribute to certain types of arthritis. This includes reactive arthritis as well as septic arthritis—an infection of joint fluid and tissues that causes joint pain and fever and requires immediate medical attention.
- Assigned sex at birth: Most types of arthritis, including osteoarthritis and rheumatoid arthritis, are more common in people assigned female at birth. Gout and ankylosing spondylitis, meanwhile, occur more frequently in people assigned male at birth.
- Family history: Rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis can run in families. If a close blood relative such as a parent or sibling has one of these conditions, you may be at a higher risk of developing arthritis as well.
How is arthritis diagnosed?
Diagnosing arthritis begins with visiting a healthcare provider (HCP), such as a primary care doctor or nurse practitioner. Your HCP will likely ask you about your symptoms and medical history. A physical exam may also be performed, during which your HCP will check for tenderness or swelling around joints and assess your joint flexibility and range of motion.
Based on your symptoms and the results of your physical exam, your HCP may order additional testing or refer you to a provider who specializes in joint disorders like arthritis, such as a rheumatologist or an orthopedist.
Can imaging exams detect arthritis?
Imaging exams play a key role in diagnosing many types of arthritis by providing HCPs with pictures of joints, cartilage, and surrounding structures. Some imaging techniques that are often used to help rule out or confirm an arthritis diagnosis include:
- X-rays: Low levels of radiation are used to produce images of joints that can reveal bone damage and cartilage loss.
- Computed tomography (CT) scan: X-rays are taken from multiple angles and combined to create cross-sectional views of joints and surrounding tissues.
- Ultrasound imaging: High-frequency sound waves are used to produce images of cartilage and soft tissues surrounding joints.
- Magnetic resonance imaging (MRI): Radio waves are combined with a magnetic field to create detailed, cross-sectional images of ligaments, tendons, and cartilage surrounding joints.
In some cases, lab tests that evaluate urine, joint fluid, or blood may be used to help identify what type of arthritis is present. For example, inflammatory proteins or high uric acid levels can point to rheumatoid arthritis or gout, respectively.
What are the possible complications of arthritis?
Untreated or poorly managed arthritis can make it difficult to perform everyday tasks like walking, getting dressed, climbing stairs, and driving a car. In some cases, arthritis can permanently alter joint shape and posture. Trouble moving around may also lead to weight gain, which can in turn make arthritis worse and increase your risk of issues like hypertension and diabetes.
People with inflammatory autoimmune types of arthritis (such as rheumatoid arthritis and psoriatic arthritis) may be at a greater risk of infections and influenza (flu) complications, either from the condition itself or the medication used to treat it. These complications include:
Rheumatoid arthritis in particular is linked to complications that can affect tissues and organs throughout the body. For example, inflammation from RA can cause:
- Gum irritation
- Skin nodules (lumps)
- Shortness of breath
- Nerve damage
Some RA complications can be life-threatening. A 2022 study published in Frontiers in Immunology found about 40 percent of people with RA experience complications, with the rate of serious complications being around 8.3 percent. These serious complications most often included cardiovascular disease, interstitial lung disease (conditions that cause lung scarring), osteoporosis, and metabolic syndrome.
When should you see a healthcare provider?
It’s always wise to consult with an HCP if you notice any new, worsening, or unusual symptoms associated with arthritis or any medical condition. With that said, consider making an appointment with your HCP if you:
- Develop joint pain that persists for more than three days
- Experience multiple episodes of joint pain within a month
Although it’s uncommon, arthritis or medications used to treat it may cause symptoms that require urgent medical attention. It’s a good idea to visit an immediate care provider if you notice:
- Sudden pain around your spine
- Rash accompanied by a high fever
- Joints that feel hot and are red, discolored, or swollen
- Sudden, intense abdominal pain
- Arthritis flare that is especially painful
In the event that you or someone around you experiences signs of a life-threatening emergency—such as chest pain, trouble breathing, or loss of consciousness—immediately call 911 or go to the nearest emergency room.
How is arthritis treated?
While arthritis isn’t reversible, it can be effectively managed in most cases. Treatment for arthritis focuses on:
- Reducing pain
- Minimizing joint damage
- Improving mobility and quality of life
Your best course of arthritis treatment will depend on what type of arthritis you have and the severity of your symptoms, along with factors like your age and overall health. The main treatment approaches for arthritis include:
There are several over-the-counter (OTC) and prescription medications that can help reduce pain and improve mobility in people with arthritis. Depending on your needs, your HCP may recommend:
- Nonsteroidal anti-inflammatory drugs (NSAIDs): Oral NSAIDs like ibuprofen and naproxen sodium can help relieve pain and inflammation, as can topical NSAIDs (diclofenac) that are available in patch, gel, and liquid form.
- Corticosteroids: Corticosteroid medications like prednisone may reduce inflammation, ease pain, and slow joint damage.
- Disease-modifying antirheumatic drugs (DMARDs): These drugs help protect joints from inflammation caused by rheumatoid arthritis and psoriatic arthritis. There are two types of DMARDs—biologic and nonbiologic—and both work by suppressing an overactive immune response. Methotrexate is a widely prescribed nonbiologic DMARD, while common biologic DMARDs for arthritis include adalimumab, golimumab, etanercept, infliximab, and several others.
- Counterirritants: When applied to an aching joint, creams and ointments containing counterirritants like menthol and capsaicin can help block pain signals from the joint to the brain.
Injection therapies that deliver corticosteroid medication directly to the joint can provide temporary pain relief for some people with osteoarthritis. Viscosupplementation, another type of injection therapy for osteoarthritis, involves administering a thick, hydrating fluid called hyaluronate into the joint space to promote smooth, comfortable movement.
Physical and occupational therapy
Physical therapy for arthritis focuses on maximizing the body’s ability to move by:
- Improving joint mobility and function
- Strengthening muscles that surround and support joints
- Preserving physical fitness
There are several techniques a physical therapist may use to help you achieve these goals. For instance, your session may involve performing gentle exercises or learning ways to reduce your joint pain at home, such as by properly using hot and cold compresses. Your HCP may recommend you attend a physical therapy session every few days, weeks, or months depending on your needs and goals. Most sessions last around one hour.
Occupational therapy is another approach to arthritis treatment. Similar to physical therapy, occupational therapy uses nonsurgical strategies to help people with arthritis perform daily tasks safely and with less pain. For example, an occupational therapist can recommend wearable devices or teach you ways to protect your joints and minimize discomfort when you clean your house, get dressed, fold laundry, and complete other basic activities.
Surgery may be appropriate for people with severe arthritis that doesn’t improve with medication, injection therapies, or physical or occupational therapy. The most common types of surgery for arthritis include:
- Joint repair surgery: Damaged joint surfaces are realigned or resurfaced to help improve mobility and reduce joint friction and pain.
- Joint fusion surgery: Two or more bones of a joint are joined together and immobilized to limit pain caused by movement. It’s most often performed in smaller joints in the ankles, wrists, and fingers.
- Joint replacement surgery (arthroplasty): Arthritic parts of a joint are removed and replaced by artificial implants (prostheses) designed to restore comfortable joint movement. Knee replacement surgery and hip replacement surgery are the most common types of joint arthroplasties.
Alternative arthritis treatment approaches
Some people find it helpful to add alternative approaches to their arthritis treatment plan, although the effectiveness of these strategies is still a subject of debate in the medical community. Check with your HCP before giving these alternative approaches a try:
- Acupuncture: In this form of Chinese medicine, very small needles are strategically placed in the skin to boost blood flow, stimulate muscles, and help activate the body’s natural pain-reducing mechanisms.
- Massage therapy: Massage can help warm arthritic joints and stimulate blood flow, both of which may reduce joint pain and stiffness.
- Tai chi and yoga: The gentle stretching movements involved in tai chi and yoga can help improve flexibility and range of motion in addition to boosting mood and overall well-being.
- Supplements: Some evidence suggests that taking nutritional supplements made with fish oil, glucosamine, or chondroitin may help provide relief from arthritis pain. Be sure to consult with your HCP before trying a new supplement, as some may interact negatively with certain medications you may be taking.
Can you prevent arthritis?
Arthritis can’t always be prevented—in fact, some medical professionals view osteoarthritis as a natural part of the aging process. Still, no one is destined for a life with joint pain. There are several steps you can take to help keep your joints healthy and stay active as you age:
- Don’t smoke cigarettes or use other tobacco products.
- Maintain a healthy body weight.
- Regularly engage in low-impact exercise, such as walking, yoga, stationary cycling, Pilates, or swimming.
- Limit alcohol, sugar, and high-purine foods like bacon, beef, venison, bison, and organ meats (these can contribute to gout).
- Thoroughly warm up and stretch when you exercise or play sports and protect your joints by wearing proper sporting equipment.
What is the outlook for arthritis?
Arthritis is a lifelong condition, but it doesn’t have to stop you from enjoying your favorite activities and living life to the fullest. With proper treatment and healthy lifestyle choices, arthritis symptoms like joint pain, stiffness, and swelling can be managed. Your HCP can help you identify arthritis treatment options for your symptoms and provide personalized guidance if your needs change.
Living with arthritis
Prioritizing exercise when you have arthritis pain may seem counterintuitive, but staying active is one of the best things you can do to keep your joints healthy. According to the CDC, adults with arthritis should try to get at least 150 minutes of moderate-intensity activity (such as brisk walking) or 75 minutes of vigorous-intensity aerobic activity (like cycling faster than 10 mph) every week. If you’re able, aim to do strength-training exercises at least two days every week and try to incorporate activities that help improve balance, like tai chi or yoga.
With this in mind, arthritis affects everyone differently. If your arthritis symptoms prevent you from exercising 150 minutes every week, do what you can and talk to your HCP about what arthritis-friendly exercises may be best for you. Remember, a little physical activity is better than none.
Maintaining a healthy body weight is also key to living well with arthritis, since carrying excess weight places added strain on joints and can accelerate the disease’s progression. In people who are overweight or obese, losing just 10 to 12 pounds may reduce arthritis pain and improve mobility, according to the CDC. Combining low-impact exercise with a joint-friendly diet (one that emphasizes fruits and vegetables, whole grains, lean meats, and healthy sources of fat like those from fish and olive oil) can help you shed excess pounds, feel better, and preserve your joint health.
Finally, arthritis may sometimes affect more than just your physical health. Living with chronic conditions like arthritis can feel frustrating, cause anxiety, and add to everyday stress. Moreover, stress may actually worsen joint pain.
To keep stress in check while living with arthritis, try adding stress-reducing techniques into your daily routine. This may include deep breathing exercises, yoga, journaling, or simply making more time for the things you love. Sharing your feelings with a loved one or speaking with a licensed mental health provider is also beneficial for many people with chronic health concerns.
Joint pain doesn’t have to slow you down. With proper treatment, lifestyle choices, and support, you can live a full and enjoyable life with arthritis.
Featured arthritis articles
American College of Rheumatology. Juvenile Arthritis. Last updated February 2023.
American College of Rheumatology. Spondyloarthritis. Last updated February 2023.
Arthritis Foundation. 8 Natural Therapies for Arthritis Pain. Accessed July 2023.
Arthritis Foundation. Biologics. Last updated September 3, 2022.
Arthritis Foundation. Gout. Accessed July 2023.
Arthritis Foundation. How Arthritis Hurts. Accessed July 5, 2023.
Arthritis Foundation. How to Reduce Your Risk of Arthritis. Accessed July 6, 2023.
Arthritis Foundation. Juvenile Idiopathic Arthritis (JIA). Accessed July 5, 2023.
Arthritis Foundation. Osteoarthritis. Accessed July 5, 2023.
Arthritis Foundation. Physical Therapy for Arthritis. Accessed July 7, 2023.
Arthritis Foundation. Psoriatic Arthritis. Accessed July 5, 2023.
Arthritis Foundation. Rheumatoid Arthritis: Causes, Symptoms, Treatments and More. Last updated October 15, 2021.
Arthritis Foundation. Topical NSAIDs Offer Joint Pain Relief. Accessed July 20, 2023.
Arthritis Foundation. What Is Arthritis? Last updated June 9, 2022.
Arthritis Foundation. When it’s Time to See a Doctor for Joint Pain. Accessed July 7, 2023.
Centers for Disease Control and Prevention. 5 Ways to Manage Arthritis. Last reviewed June 12, 2023.
Centers for Disease Control and Prevention. FAQs About Arthritis. Last reviewed October 12, 2021.
Centers for Disease Control and Prevention. Gout. Last reviewed July 27, 2020.
Centers for Disease Control and Prevention. Osteoarthritis (OA). Last reviewed July 27, 2020.
Centers for Disease Control and Prevention. Osteoarthritis. Last reviewed June 12, 2023.
Centers for Disease Control and Prevention. Physical Activity for Arthritis. Last reviewed January 5, 2022.
Centers for Disease Control and Prevention. Rheumatoid Arthritis. Last reviewed April 7, 2022.
Cleveland Clinic. Arthritis. Last reviewed April 15, 2021.
Cleveland Clinic. Osteoarthritis. Last reviewed November 26, 2019.
Johns Hopkins Medicine. About Arthritis and Other Rheumatic Diseases. Accessed July 5, 2023.
Johns Hopkins Medicine. Juvenile Rheumatoid Arthritis. Accessed July 12, 2023.
Johns Hopkins Arthritis Center. Psoriatic Arthritis. Accessed July 6, 2023.
Mayo Clinic. Arthritis. Last updated September 15, 2021.
Mayo Clinic. Psoriatic Arthritis. Last updated October 2, 2021.
MedlinePlus. Uric Acid–Blood. National Library of Medicine. Last reviewed May 1, 2021.
National Institute of Arthritis and Musculoskeletal and Skin Diseases. Juvenile Idiopathic Arthritis (JIA). Last reviewed May 2021.
National Institute of Arthritis and Musculoskeletal and Skin Diseases. Overview of Ankylosing Spondylitis. Last reviewed May 2023.
National Institute of Arthritis and Musculoskeletal and Skin Diseases. Reactive Arthritis. Last reviewed September 2021.
Wu Di, Luo Yehao, Li Tong, Zhao Xinyi, Lv Ting, Fang Gang, Ou Peiqi, Li Hongyi, Luo Xiaofan, Huang An, Pang Yuzhou. Systemic complications of rheumatoid arthritis: Focus on pathogenesis and treatment. Frontiers. December 9, 2022.