Arthritis is a common condition that causes pain and inflammation in a joint.
In the UK, around 10 million people have arthritis. It affects people of all ages, including children (see below).
Types of arthritis
The two most common types of arthritis are osteoarthritis and rheumatoid arthritis.
Osteoarthritis is the most common type of arthritis in the UK, affecting around 8 million people.
It often develops in people who are over 50 years of age. However, it can occur at any age as a result of an injury or another joint-related condition.
Osteoarthritis initially affects the smooth cartilage lining of the joint. This makes movement more difficult than usual, leading to pain and stiffness.
The cartilage lining of the joint can then thin and tissues within the joint can become more active. This can then lead to swelling and the formation of bony spurs, called osteophytes.
In osteoarthritis, the cartilage (connective tissue) between the bones gradually erodes, causing bone in the joints to rub together. The joints that are most commonly affected are those in the hands, spine, knees and hips.
In the UK, rheumatoid arthritis affects more than 400,000 people. It often starts when a person is between 40 and 50 years old. Women are three times more likely to be affected than men.
Rheumatoid and osteoarthritis are two different conditions. Rheumatoid osteoarthritis occurs when the body's immune system targets affected joints, which leads to pain and swelling.
The outer covering (synovium) of the joint is the first place affected. This can then spread across the joint, leading to further swelling and a change in the joint's shape. This can cause the bone and cartilage to break down.
People with rheumatoid arthritis can also develop problems with other tissues and organs in their body.
Other types of arthritis and related conditions
Ankylosing spondylitis – a long-term inflammatory condition that mainly affects the bones, muscles and ligaments of the spine, leading to stiffness. Other problems can include the swelling of tendons, eyes and large joints.
Cervical spondylosis – also known as degenerative osteoarthritis, cervical spondylitis affects the joints and bones in the neck, which can lead to pain and stiffness.
Fibromyalgia – causes pain in the body's muscles, ligaments and tendons.
Lupus – an autoimmune condition that can affect many different organs and the body's tissues.
Gout – a type of arthritis caused by too much uric acid in the body. This can be left in joints (usually affecting the big toe) but can develop in any joint. It causes intense pain and swelling.
Psoriatic arthritis – an inflammatory joint condition that can affect people with psoriasis.
Enteropathic arthritis – a form of chronic, inflammatory arthritis associated with inflammatory bowel disease (IBD), the two best-known types being ulcerative colitis and Crohn's disease. About 1 in 5 people with Crohn's or ulcerative colitis will develop enteropathic arthritis. The most common areas affected by inflammation are the peripheral (limb) joints and the spine.
Reactive arthritis – this can cause inflammation of the joints, eyes and urethra (the tube that urine passes through). It develops shortly after an infection of the bowel, genital tract or, less frequently, after a throat infection.
Secondary arthritis – a type of arthritis that can develop after a joint injury and sometimes occurs many years afterwards.
Polymyalgia rheumatica – a condition that affects people over 50 years of age, where the immune system causes muscle pain, stiffness and joint inflammation.
Symptoms of arthritis
The symptoms of arthritis you experience will vary depending on the type you have.
This is why it's important to have an accurate diagnosis if you have:
joint pain, tenderness and stiffness
inflammation in and around the joints
restricted movement of the joints
warm, red skin over the affected joint
weakness and muscle wasting
Arthritis and children
Arthritis is often associated with older people, but it can also affect children. In the UK, about 15,000 children and young people are affected by arthritis.
Most types of childhood arthritis are known as juvenile idiopathic arthritis (JIA). JIA causes pain and inflammation in one or more joints for at least six weeks.
Although the exact cause of JIA is unknown, the symptoms often improve as a child gets older, meaning they can lead a normal life.
The main types of JIA are discussed below. You can also read more about the different types of juvenile idiopathic arthritis on the Arthritis Research UK website.
Oligo-articular JIA is the most common type of JIA. It affects fewer than five joints in the body – most commonly in the knees, ankles and wrists.
Oligo-articular JIA has good recovery rates and long-term effects are rare. However, there's a risk that children with the condition may develop eye problems, so regular eye tests with an ophthalmologist (eye care specialist) are recommended.
Polyarticular JIA (polyarthritis)
Polyarticular JIA, or polyarthritis, affects five or more joints. It can develop at any age during childhood.
The symptoms of polyarticular JIA are similar to the symptoms of adult rheumatoid arthritis. The condition is often accompanied by a rash and a high temperature of 38°C (100.4°F) or above.
Systemic onset JIA
Systemic onset JIA begins with symptoms such as a fever, rash, lethargy (a lack of energy) and enlarged glands. Later on, joints can become swollen and inflamed.
Like polyarticular JIA, systemic onset JIA can affect children of any age.
Enthesitis-related arthritis is a type of juvenile arthritis that affects older boys or teenagers. It can cause pain in the soles of the feet and around the knee and hip joints, where the ligaments attach to the bone.
There's no cure for arthritis, but there are many treatments that can help slow down the condition.
For osteoarthritis, painkillers, non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids are often prescribed.
In severe cases, the following surgical procedures may be recommended:
arthroplasty (joint replacement)
arthodesis (joint fusion)
osteotomy (where a bone is cut and re-aligned)
In treating rheumatoid arthritis, the aim is to slow down the condition's progress and minimise damage to the joints. Recommended treatments include:
disease modifying anti-rheumatic drugs (DMARDs)
Further information and support
Arthritis Research UK and Arthritis Care provide more information about arthritis, as well as advice and support for people living with arthritis.