© 2019 OA Knee Pain. All Rights Reserved.

What Are The Differences Between OA And Other Types Of Arthritis?

18th April 2019

Find an OA Knee Pain expert

There are over 100 different types of arthritis. The most common include osteoarthritis (OA), rheumatoid arthritis (RA), psoriatic arthritis (PsA), ankylosing spondylitis (AS), fibromyalgia and gout.

Although there are many similarities between the different types of arthritis and the pain they cause, knowing which type you have can make the difference between successful treatment or further debilitation.


Arthritis is an overreaching medical term which covers a wide range of conditions affecting the joints and surrounding tissues. Different types of arthritis can affect parts of the body in different ways, but the common symptoms include stiffness, swelling and joint pain.

Although often considered an old person’s illness, arthritis affects more than 10 million people in the UK including many young adult and child sufferers.

Unfortunately, there is no cure for arthritis at present, however researchers have developed a number of treatments which can help slow down the condition. Physiotherapy and exercise as well as a Vitamin D rich diet can significantly improve the quality of life for someone suffering with arthritis and establishing what type you have will ensure that you receive the correct treatment.


OA is by far the most common form of arthritis, affecting nearly 9 million people in the UK. It can occur at any age but is most common in women over the age of 40 with a family history of the condition.

When not inherited, OA generally occurs as a result of an injury or other joint-related condition. It happens when the smooth cartilage of a joint wears out, forcing tendons and ligaments to work harder in order to take up the strain from the roughened cartilage. This leads to severe pain, stiffness and the formation of bony spurs called osteophytes forming on the swollen area of the joint.

In extreme cases, the loss of cartilage can lead to the bones rubbing together, altering the shape of the joint and forcing the bones out of their usual positions. Due to this, OA is considered a degenerative disease as the cartilage will continue to wear down over time if left untreated.

One of the main problems with OA is how long it can take to be diagnosed, with some referring to it as a ‘silent disease’ due to the number of years it is possible to have OA before the first symptoms - immobility or extreme pain following exercise - manifest.

Once symptoms start to show, OA is diagnosed by way of a bone mineral density test which will show whether a patient is suffering from low bone density: a sign they may be suffering from OA.

Rheumatoid Arthritis

While OA involves the cartilage in the joint wearing down, RA is an autoimmune disease and the second most common form of arthritis. In the UK, RA affects over 400,000 people, with women three times more likely to be affected than men. Most RA sufferers develop the disease when they are between 40 - 50 years old, however, it can affect anyone at any time.

An autoimmune disease refers to the immune system malfunctioning and attacking healthy tissue rather than protecting the body from viruses as it should. In RA, the immune system attacks the synovial membrane, which is the lining that protects the joints. Similarly to OA, this is a degenerative disease as the inflammation breaking down the membrane is persistent and can damage joints permanently if left untreated.

RA won’t just stop at the synovium however; it will also cause the immune system to attack healthy cells in other parts of the joint such as bones and ligaments. People diagnosed with RA will notice that it often targets multiple joints at the same time, causing still further pain and discomfort.

As this disease affects the immune system, symptoms of RA will often include fevers, anaemia, fatigue, rheumatoid nodules under the skin, loss of appetite as well as the usual complaints of a loss of mobility and pain around the joints. This is due to the immune system attacking the body rather than foreign cells, so not only does RA wear down the joints but it also distracts the immune system from keeping the body healthy. Other symptoms can also be observed in the heart, lungs, eyes and skin for some patients.

Psoriatic Arthritis

PsA is another autoimmune disease which causes the immune system to attack the joints and skin as well as causing inflammation, joint pain and stiffness. As with many other types of arthritis, this disease is degenerative and can affect the entire body, causing permanent joint and tissue damage.

Most people who have developed PsA will have experienced skin symptoms first as ‘psoriasis’ is a skin disease causing itchy, scaly rashes. Around 30% of people with psoriasis will develop PsA, although it is possible to contract PsA without having had psoriasis first.

In many cases, PsA will exist in the body long before symptoms show, with the disease being triggered by an outside event such as a throat infection, awakening the PsA and confusing the immune system into attacking the healthy body.

Ankylosing Spondylitis

AS or Ankylosing Spondylitis is a chronic inflammatory condition which involves the spine and other areas of the body swelling, causing stiffness with the potential for joints to fuse together. AS mainly affects the bones, muscles and ligaments of the spine as well as swollen tendons, eyes and joints.

Conversely to other types of arthritis, AS generally develops slowly in young adults and may improve or worsen over time depending on the individual, with phases of improvement / degeneration during the sufferers’ lifetime.

The symptoms of AS usually involve back pain and stiffness, inflammation of the joints or tendons and extreme fatigue, however there are many other symptoms of AS and patients may report a wide variety of complaints linked to the disease.

Thankfully, AS doesn’t tend to significantly affect life expectancy, with 70 - 90% of people reporting they have been able to remain fully independent and only minimally disabled as a result of the disease.

That said, if the bones in the spine do fuse together, this can cause severe disability and damage to other joints - commonly the hips and knees.


Fibromyalgia is categorised as a central pain syndrome, occurring when the pain receptors in the brain and spinal cord disagree. This causes fibromyalgia sufferers to experience pain far more strongly than those who don’t have the disease, either as allodynia (a touch or movement which doesn’t usually cause a person pain hurts) or hyperalgesia (touch or movement which might mildly hurt a non-sufferer is extremely painful).

Other symptoms of fibromyalgia include fatigue, lack of concentration, irritability and widespread pain across the body, either on occasion or as constant pain.

Due to the varying symptoms and unclear causes, fibromyalgia can be difficult to identify and a diagnosis of this condition will usually only be given if other conditions which could cause the chronic pain and fatigue are ruled out following a physical exam.


Gout is another form of inflammatory arthritis involving the accumulation of urate crystals inside the joints.

Gout is usually caused when a person has high levels of uric acid in their blood or they are unable to remove excess uric acid quickly enough, allowing crystals to form in the joints.

Most commonly, gout affects the large joint in the big toe, causing an extremely painful joint inflammation, however, it can occur in any joint throughout the body.

Gout symptoms often come and go throughout a patient’s lifetime and can come on incredibly quickly during the course of a day, lingering anywhere from a few hours to days or even weeks.

The disease is often contracted by those with a family history of gout and is more commonly found in men than women. A person’s age, diet and alcohol consumption can also increase the risk of developing gout, even if there is no family history, and it will frequently become more severe over time.


Unfortunately, there is currently no cure for any type of arthritis, with treatments instead focusing on slowing down the progression of the disease.

For OA, treatments tend to include focusing on a patient’s diet and exercise, pain relieving medication and potentially surgery to repair, replace or strengthen damaged joints. The treatments recommended will depend on which joint(s) have been affected by OA and surgery will usually only be considered as a last resort.

For RA sufferers, treatments are generally similar, including pain relieving medication, physiotherapy and surgery as a last resort, all aiming to slow down the progress of the condition and reduce the inflammation in the joints to prevent permanent damage.

Sign up to the OA Knee Pain newsletter