Arthritis Types – Your Questions Answered

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.

Arthritis statistics

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 research²using 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.

Osteoarthritis

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

Rheumatoid arthritis

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

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

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

Reactive arthritis

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

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

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.

Don’t let arthritis bring you to a halt – book today and get back to being you!

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