What causes arthritis?

The most common cause of arthritis is osteoarthritis - sometimes called wear and tear or age-related change to the joints. When people talk about arthritis alone, they usually mean osteoarthritis. Other causes of arthritis include autoimmune conditions - like rheumatoid arthritis - gout, and infections.

If you think you have arthritis find out what to do here. This will tell you if you need to see a doctor and how to treat it.

In this series of articles centred around arthritis you can read about arthritis causes, arthritis symptoms, and arthritis treatment - all written by one of our expert GPs.

The rest of this feature will take an in-depth look at the treatments of arthritis as, at Patient, we know our readers sometimes want to have a deep dive into certain topics.

What causes arthritis?

Arthritis has lots of different causes and affects people of all ages. Common types of arthritis include:

Osteoarthritis

Osteoarthritis is caused by damage to the joint, usually over a long period of time. Osteoarthritis is closely linked with age, and it's more common in older people.

Other reasons for osteoarthritis developing include extra weight on the joints - obesity or overweight - and repeated injury or overuse of a joint. See osteoarthritis causes for more detail.

Osteoarthritis can affect any joint in the body but commonly affects the hips, knees, spine, and hands.

Autoimmune conditions

Various different autoimmune conditions can cause joint inflammation and arthritis when the body's immune system mistakenly attacks the lining of the joints.

Types of autoimmune arthritis include:

• Rheumatoid arthritis - the most common form of autoimmune arthritis.

• Juvenile idiopathic arthritis - the most common cause of long-lasting arthritis in children and young adults.

• Psoriatic arthritis - typically affects people with psoriasis.

• Ankylosing spondylitis - typically affects the neck and spine - there is usually a gene, HLA-B27, that makes this more likely and can be tested for.

• Arthritis associated with inflammatory bowel disease (IBS) - sometimes called enteropathic arthritis.

• Reactive arthritis - a type of autoimmune arthritis that occurs in reaction to an infection elsewhere in the body. Usually from a sexually transmitted infection or a gut infection which causes pain and inflammation in joints.

• Arthritis seen as part of systemic lupus erythematosus (SLE) - or lupus.

Other causes of arthritis

These conditions are different, and have their own patterns of symptoms. They can also affect things outside the joints.

Gout

Gout is a common cause of arthritis which typically causes flares where an affected joint becomes very painful, and often red and swollen. Gout is caused by too much urate in the blood. This can enter joints and form tiny crystals, leading to inflammation, pain, and swelling.

Gout classically affects the joint at the base of the big toe but can affect other joints too.

Calcium pyrophosphate deposition (CPPD) - sometimes called pseudogout - is similar to gout and causes similar symptoms.

Infection

Septic arthritis is an infection of a joint - usually bacterial. It can cause symptoms of arthritis and usually affects a single joint and leads to pain, swelling, redness, and other symptoms of infection such as a fever.

Other conditions

Joint pain is a symptom of some other conditions which usually aren't considered types of arthritis, but can sometimes produce similar symptoms. Examples include:

• Ehlers-Danlos syndrome - people with hypermobile Ehlers-Danlos syndrome can get joint pain, and may be at higher risk of osteoarthritis.

• Fibromyalgia - can cause widespread pain in the muscles which can cause joint pain.

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by Victoria Raw

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Chondrocalcinosis

Chondrocalcinosis is very common but only tends to cause symptoms when it is caused by an underlying condition, such as osteoarthritis.

by Dr Colin Tidy, MRCGP

Does cracking your knuckles cause arthritis?

Studies have shown there is no link between knuckle cracking and arthritis.

How common is arthritis?

The NHS estimates around 10 million people in the UK have a form of arthritis. More than 8.5 million people have osteoarthritis. Autoimmune arthritis is less common - for example, around 440,000 people in the UK have rheumatoid arthritis.

What causes arthritis flare-ups?

Common symptoms of arthritis flare-ups include swelling, pain, and stiffness that gets worse over a few days. Across the different types of long term (chronic) arthritis, the causes of flare-ups vary - they include:

• Osteoarthritis - overdoing an activity, stress, repetitive motions, cold weather, an infection, or weight gain.

• Rheumatoid arthritis and many other types of autoimmune arthritis - stopping medication, stress, overexertion, other infections, or poor sleep.

• Gout - drinking too much alcohol, eating large fatty meals, being dehydrated, taking certain medications, or injuring a joint.

Risk factors for arthritis

Risk factors vary depending on the type of arthritis, but examples include:

• Age - osteoarthritis and gout are more common in older adults and rheumatoid arthritis most commonly develops in middle age.

• Gender - rheumatoid arthritis is more common in women, whereas gout is more common in men.

• Family history - some causes of arthritis have a genetic component, so having a family member with that condition increases your risk of developing it. Examples include rheumatoid arthritis, systemic lupus erythematosus, and ankylosing spondylitis.

• Smoking - increases the risk of some conditions, such as rheumatoid arthritis.

• Overweight and obesity - extra weight can put more strain on the joints and increase the risk of osteoarthritis.

See osteoarthritis causes for more specific risk factors.

How to prevent arthritis

Arthritis can't be fully prevented. However, there are some things that can reduce the risk of it developing - these have other health benefits as well.

• Eating a healthy diet - including avoiding processed and sugary foods can reduce the risk of getting gout.

• Reducing, or avoiding, alcohol consumption - can help reduce the risk of gout.

• Stopping, or avoiding, smoking - reduces the risk of rheumatoid arthritis.

• Maintaining a healthy weight, including losing weight - can reduce the risk of osteoarthritis as well as helping with symptoms of arthritis if they are already present.

• Regular exercise - particularly low-impact exercise like swimming, yoga, and Pilates can help to keep joints healthy. Many find that regular exercise reduces pain in arthritis.

Further reading

• About Arthritis; Versus Arthritis.

• Arthritis Foundation.

• The State of Musculoskeletal Health 2021 - Arthritis and other musculoskeletal conditions in numbers; Versus Arthritis.