Arthritis is one of the most common causes of pain and disability in the UK. But did you know there are more than 100 types of arthritis? If you have arthritis, you may be wondering which kind, or what might help, or how it’s likely to progress. In this article, we look at the most common forms of arthritis and answer the questions we most often hear in clinic.
Here are some interesting facts and figures about arthritis in the UK:
- Osteoarthritis is the most common form of arthritis, affecting nearly 9 million people.
- 430,000 people have rheumatoid arthritis.
- Although we associate arthritis with ageing, it can also affect younger people. Juvenile idiopathic arthritis affects around 12,000 under-16s.
- Axial spondyloarthritis is not well known, but affects around 1 in 200 adults, making it more than twice as common as Parkinson’s disease.
- Osteoarthritis affects 10% of men and 18% of women. The knee is the most affected joint1.
What is arthritis?
‘Arthritis’ is a collective term for a large group of conditions that cause pain and inflammation in a joint. These conditions have many causes. Different types of arthritis prefer different joints. Some types of arthritis can affect one joint, and some many joints. Some can also cause problems in other parts of the body, such as the heart, lungs or skin.
In general terms, types of arthritis can be first classified into two groups – inflammatory and non-inflammatory.
Inflammatory or non-inflammatory?
You might be wondering how we can call some types of arthritis ‘non-inflammatory’ when we’ve just defined arthritis as a condition that causes pain and inflammation.
In fact, the definition isn’t clear cut. Historically, some types of arthritis (such as osteoarthritis) were seen as ‘degenerative’, i.e. to do with breakdown of tissues, and not involving inflammation. Whereas other forms appeared to be triggered by systemic inflammation, such as rheumatoid arthritis or psoriatic arthritis, which are autoimmune conditions.
People living with osteoarthritis know all too well, however, that they can have inflammation in their joints. This has generally been thought to be due to tissue breakdown irritating and inflaming the joint lining.
More recent research2 using MRI imaging, though, shows that signs of inflammation can be present in an osteoarthritic joint before any tissue breakdown has occurred. It’s not yet clear whether this inflammation might be a trigger that causes osteoarthritis to develop. But if it is, then it opens promising new avenues for treatment and prevention.
Types of arthritis
Let’s have a closer look at some of the more common forms of arthritis.
By far the most common form of arthritis, osteoarthritis was once considered a normal state of ‘wear and tear’ in an ageing joint. While there does appear to be a link with mechanical damage to a joint, it’s now known that osteoarthritis isn’t an inevitable state of age. It’s a pathological, rather than a normal, process.
The bones in your joints are edged with smooth cartilage, which allows gliding of the joint during movement. The joint is contained within a tough, fibrous capsule. This is lined with a membrane, called ‘synovium’, that produces the fluid that fills and bathes the joint.
Sometimes, the surface of the cartilage becomes roughened. This can then lead to thickening of the synovial lining, which becomes rubbery and produces more fluid, causing soft swelling. The joint capsule can become stretched, which then causes the joint to feel unstable. The body therefore tries to stabilise the joint by laying down extra bone around the edges. That’s why arthritic joints can feel enlarged and solid, and become stiff.
Do I have it?
|Risk factors||Obesity, joint injury, abnormal joint shape or malalignment, poor muscle strength, increasing age, female gender, metabolic conditions such as diabetes, family history|
|Typical age of onset||From mid-40s, risk increases with age|
|Joints affected||Weightbearing (knees, hips, feet, lower back) and most used (fingers, base of thumb, neck, jaw), but any joint can be affected|
|Symptom pattern||Pain, especially on moving after rest. Grating noise or sensation. Swelling, may be hard due to bony enlargement, or soft due to enlarged joint lining and increased fluid production. Joint may feel unstable in earlier stages and progress to being stiff|
|Associated symptoms||Effects are local, but sufferers may also experience depression, anxiety and sleep disturbance due to pain and loss of mobility|
An autoimmune disease, rheumatoid arthritis (RA) is a condition in which your immune system attacks healthy joint tissues.
Inflammation, which is part of the immune defence system, builds up inside the joint, causing swelling. This can overstretch the joint’s connective tissue capsule, which then can’t return to normal once the swelling subsides.
Instead of supporting the joint in its normal position, the stretched capsule means the joint has extra movement. The body then tries to stabilise the joint by laying down extra bone. The whole process can result in pain, swelling, stiffness and joint deformity.
RA can affect people of all ages – it’s not a disease of the elderly – though most people are in the 40-60 age range when they receive a diagnosis. Although it’s called ‘arthritis’, joints are only one area that the condition affects. In about 40% of people, the widespread inflammation of RA can also damage eyes, lungs, heart, kidneys, salivary glands, nerves, bone marrow and blood vessels3.
Do I have it?
|Risk factors||Smoking, obesity, female gender, family history|
|Typical age of onset||Any age, though diagnosis more common during middle age|
|Joints affected||Multiple joints affected symmetrically. Mid-finger (rarely end-finger), knuckle and wrist joints, toes, then ankles, elbows, knees, shoulders, hips|
|Symptom pattern||Joints are tender, warm and swollen. Joints feel stiff after rest. Often accompanied by low-grade fever, fatigue and loss of appetite|
|Associated symptoms||Breathlessness, chest pain, dry eyes and mouth, development of firm nodules under skin, commonly around elbows|
Psoriatic arthritis is also an autoimmune condition, like RA. It occurs in around one-third of people who have the skin condition psoriasis. It usually takes 5-10 years after the onset of psoriasis to develop. It can affect any joint, although it’s seen more often in knees, ankles, hands and feet.
Do I have it?
|Risk factors||Genetic susceptibility plus an environmental trigger that might be an infection, an injury, being overweight or smoking|
|Typical age of onset||5-10 years following diagnosis of psoriasis (though occasionally occurs before psoriasis is diagnosed)|
|Joints affected||Hands, feet, wrists, knees, ankles|
|Symptom pattern||Morning stiffness, or after inactivity, that lasts more than 30 minutes. Tenderness, redness and swelling around joints|
|Associated symptoms||Fatigue; swollen fingers (dactylitis); tenderness and swelling where tendons or ligaments join to bones (enthesitis), often at the back of the heel; pitting, flaking and discolouration of nails|
Axial spondyloarthritis (axSpA) is a progressive, inflammatory arthritis that mainly affects the spine and pelvic joints at the base of the back (sacroiliac joints).
It starts with inflammation of the areas where tendons or ligaments join to bone. Some of the bone at these sites wears away. As the body lays down new bone, some of the tendon or ligament is also changed to bone. This process means the bones of the spine start to fuse, causing increasing stiffness.
There are two types of axSpA. In one type, changes around the joints are visible on X-ray. This type is known as ‘ankylosing spondylitis’. In the other type, known as ‘non-radiographic axial spondyloarthritis’, people have the symptoms that indicate inflammatory changes. These can’t be seen on X-ray, but they may or may not be visible by MRI.
It was once thought that axSpA was more common in men, but medics now think that women are equally likely to develop it. Women seem to present with more widespread pain, often leading to misdiagnosis with other conditions, such as fibromyalgia.
As with other inflammatory arthritis conditions, symptoms can appear in other parts of the body. Around 25% of people with axSpA have periods of inflammation of the front part of the eye, causing blurred vision, pain, redness and sensitivity to light. In addition, about 7% of people with axSpA also have inflammatory bowel disease. This can produce abdominal pain and bloating, diarrhoea, constipation, loss of appetite, blood and mucus in the stools and fatigue.
Do I have it?
|Risk factors||Genetics (having the HLA-B27 gene), inflammatory bowel disease and osteoporosis (these don’t cause axSpA, but there is a link), smoking, obesity, high blood pressure, high cholesterol levels, diabetes|
|Typical age of onset||Affects younger people, often those in their teens or twenties. Almost all diagnoses are made before age 40|
|Joints affected||In men, mainly spine and sacroiliac joints, though others can be affected. In women, often arm, leg and neck joints first affected, and more ‘all-over’ body pain|
|Symptom pattern||Stiffness in the morning or after inactivity that lasts more than 30 minutes|
|Associated symptoms||Fatigue; widespread body pain; tenderness and swelling where tendons or ligaments join to bones (enthesitis), often at the back of the heel; eye pain, redness and blurred vision; stomach pain and bowel symptoms; psoriasis|
Juvenile idiopathic arthritis
Another autoimmune disease, juvenile idiopathic arthritis (JIA) affects children under 16. In fact, it’s most common in pre-school age children.
The causes are unknown but may be related to genetic factors combining with environmental ones. It’s possible that a normal immune reaction to an infection carries on after the infection has gone, affecting the joints.
There are several types of JIA. The most common, oligoarthritis, (‘oligo‘ means ‘few’) tends to affect the knees and is self-limiting. Pain and redness of the eye (uveitis) often come with it.
Other types may continue into adulthood. Some are associated with enthesitis or psoriasis. Systemic-onset JIA is the most rare, and it causes body-wide inflammation, joint pain and swelling.
Look out for joint pain, redness and swelling, fatigue, fever, and a limp without injury.
Do I have it?
|Risk factors||Unknown. Likely to be a combination of genetics (such as a family member with axSpA) and environment (such as an infection)|
|Typical age of onset||Age under 16|
|Joints affected||Depends on the type. In the most common form, knees are affected|
|Symptom pattern||Joint warmth, redness, tenderness. Limp without injury. Fever|
|Associated symptoms||Fatigue; tenderness and swelling where tendons or ligaments join to bones (enthesitis), often at the back of the heel; eye pain, redness and blurred vision; stomach pain and bowel symptoms; psoriasis|
As with many other forms of arthritis, reactive arthritis is to do with overactivity of the immune system. It follows an infection, such as a sore throat, stomach bug or sexually-transmitted infection. You’ll experience extreme fatigue, joint pain and swelling, usually in the knees or ankles, soon after the infection.
Other symptoms can include eye redness, soreness and discharge (conjunctivitis), scaly rash on the hands or feet, soreness when urinating, mouth ulcers and fever.
It generally lasts between three months and a year, although some people will have ongoing flare-ups or develop another type of arthritis.
Do I have it?
|Risk factors||Recent history of infection, which may be mild. Having the HLA-B27 gene (which is associated with other forms of arthritis) also slightly increases your risk|
|Typical age of onset||All ages|
|Joints affected||Mainly knees and ankles|
|Symptom pattern||Pain, stiffness, swelling and warmth in affected joints|
|Associated symptoms||Fatigue; swelling of fingers or toes (dactylitis); soreness and swelling of eye (conjunctivitis); soreness on urinating; scaly rash on hands or feet; mouth ulcers; fever|
Gout is the most common form of inflammatory arthritis. It happens when crystals of uric acid build up inside the joints and cause pain and inflammation. Uric acid is formed from the breakdown of purines, which are a by-product of certain bodily processes or come from food. Normally, we can flush out excess uric acid in urine, but if there’s a problem with that process, crystals can form in the joints or under the skin.
Do I have it?
|Risk factors||Male gender, obesity, diabetes, high blood pressure or cholesterol, kidney disease|
|Typical age of onset||In men, gout can occur at any age, though the risk increases with age. In women, it’s unusual to develop gout before menopause|
|Joints affected||Typically starts in the big toe knuckle joint, but also other joints of the feet, ankles, knees elbows, wrists and fingers|
|Symptom pattern||An attack often starts in the early hours of the morning. The joint becomes very painful, hot, red and swollen, with shiny skin over it. Even light contact, such as from a bedsheet, can be unbearable|
|Associated symptoms||Tophi – small lumpy collections of urate crystals. Tophi can be seen under the skin, often on toes, heels, knees, fingers, elbows and ears|
Polymyalgia rheumatica (PMR) is a condition causing muscle and joint pain and stiffness in the shoulders (70-95%) and hips (50-70%). It can also cause aching in the neck, upper arms and thighs.
The aching and stiffness can be severe, causing difficulty reaching, climbing stairs or getting up from a chair. This pain tends to be worse with rest and eases with activity. It happens in people over 50 and is more common in those over 70. Women are two to three times more likely than men to have PMR.
People who have PMR are significantly more likely to experience an inflammatory condition of arteries in the head, called ‘giant cell arteritis’ (GCA). These arteries are located at the temples, which can become swollen and tender. People with GCA often have severe headaches, scalp tenderness, blurred vision, or pain around the jaw when chewing. GCA puts someone at greater risk of stroke or loss of eyesight, so it should be treated quickly.
Do I have it?
|Risk factors||Genetics (possible link to the HLA-DR4 gene that is associated with rheumatoid arthritis), infection (PMR often comes on suddenly soon after a bout of flu-like illness). Possible link to overexposure to ultraviolet light, which may damage the arteries near the skin. 2-3x more women than men affected|
|Typical age of onset||Almost always over 50, most common over 70|
|Joints affected||Shoulders, hips. Occurs on both sides|
|Symptom pattern||Aching and stiffness after rest that lasts more than 30 minutes, and eases with activity|
|Associated symptoms||Fatigue; feeling unwell; headache, scalp and face tenderness, blurry vision (GCA)|
Looking for help with your arthritis?
There are plenty of ways to help manage pain and stiffness. Our qualified and experienced team of therapists can offer manual therapy, nutritional therapy, acupuncture, massage and exercise planning, plus support, advice and guidance.
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- Mathiessen, A., Conaghan, P.G. Synovitis in osteoarthritis: current understanding with therapeutic implications. Arthritis Res Ther 19, 18 (2017). https://doi.org/10.1186/s13075-017-1229-9
- Kim, J. W., & Suh, C. H. (2020). Systemic Manifestations and Complications in Patients with Rheumatoid Arthritis. Journal of clinical medicine, 9(6), 2008. https://doi.org/10.3390/jcm9062008
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