Joint pain

There are many possible causes of joint pain — referred to medically as arthralgia — although injury and arthritis are the most common. Joint pain can affect one joint or multiple joints depending on the cause. 

Joints commonly affected are the hip, knee, shoulder, wrists and fingers. Knees are one of the joints most often damaged as they take your full body weight and extra force when running, jumping or dancing. This means you're more at risk of joint pain if you're overweight or do a lot of sports.

If you are older and have pain in a joint that gradually gets worse with age, you may have osteoarthritis. Osteoarthritis can affect one or several joints and you should see your GP if you have persistent osteoarthritis symptoms.

Joint pain can be caused by problems with different structures in and around your joint. This includes:

• Bones — either those that comprise your joints or nearby bones
• Synovia (linings of the joints)
• Tendons, ligaments and muscles around your joint

Joint pain can also be caused by pain elsewhere in your body that affects a nerve — this is called referred pain eg a hip problem may cause knee pain in addition to hip pain. 

Some conditions commonly affect one joint but can in some cases affect several joints. Similarly, some conditions that commonly affect multiple joints can affect just one joint, especially at the start of the condition. 

Injury

Sudden pain and swelling in a joint may be caused by an injury, such as a fracture or a tear (a sprain) to a tendon, ligament or cartilage. You may also experience bleeding into the joint space after an injury, which is called haemarthrosis — signs include bruising and stiffness, which may occur soon after injury, swelling of the joint and warmth. Haemarthrosis is more likely if you’re taking anticoagulants (blood thinners). If you think you have injured a joint and it's causing severe pain, you should go to A&E right away.

Joint pain affecting your knee that worsens when you go up or down the stairs may be caused by damage to the cartilage at the back of your kneecap — this is called chondromalacia patellae. This condition does not cause heat or redness and is linked to overuse of the knee. Treatment includes anti-inflammatory medicines, placing an ice pack against your knee and rest.

Inflammation

Pain in just one joint could be inflammation of a tissue in your joint. It's often accompanied by swelling and tenderness. Inflammation can be caused by many conditions, including:

• Bursitis — inflammation of the bursa (a fluid-filled sac that cushions your bones)
• General body infection — flu-like illnesses that cause a high temperature (fever) can cause many or all of your joints to become painful
• Synovitis — inflammation of the joint lining, which can occur after an injury
• Tendonitis — injury and inflammation in a tendon eg tennis elbow

Arthritis

There are many types of arthritis — a range of conditions that cause pain and stiffness in your joints. The most common that are likely to cause joint pain are:

• Gout or pseudogout — gout usually affects your big toe first and then your other joints, while pseudogout affects your knee first; both cause sudden intense pain, in repeated attacks, with heat and red skin around your joint and if you think you have either, you should see your GP 
• Lupus — a chronic (long-term) condition causing inflammation in your joints but also your skin and other organs
• Osteoarthritis — joint pain that gradually gets worse affecting one or many joints; it is more common in older people and can also cause ganglion cysts to develop
• Psoriatic arthritis­ — this affects one in five people with psoriasis, making joints painful, stiff and swollen; although flare-ups are unpredictable, they can usually be controlled with medication
• Rheumatoid arthritis — this usually causes pain in many joints, often the hands, feet and wrists; the pain can come and go and you may feel tired and flu-like
• Septic arthritis — an infection in a joint that causes pain, heat, swelling and fever; if you have septic arthritis you should go to A&E

Arthritis that causes joint pain can also occur due to infection with a virus eg viral hepatitis (liver inflammation caused by a virus) and rubella (a viral infection once common in children).

Less common causes of joint pain affecting one joint

• Avascular necrosis — crumbling of your bone due to reduced or no blood supply
• Cancer
• Haemophilia — an inherited genetic disorder that reduces your body's ability to form blood clots
• Infections that cause reactive arthritis, which usually affects young adults, and tropical infections (eg chikungunya virus)
• Injuries that cause fractures or repeated dislocation of your joint
• Osgood-Schlatter's disease — irritation, swelling and tenderness around the bony bump just below your kneecap

Causes of joint pain in specific joints

Knee pain and kneecap pain (patellofemoral pain) can be caused by: 

• Housemaid's knee — the medical name for this is prepatellar bursitis
• Knee ligament injuries
• Meniscal tears — injury to the cartilage of your knees

Elbow pain can be caused by: 

• Student's elbow — the medical name for this is olecranon bursitis 
• Tennis elbow — this is a type of tendonitis (injury and inflammation in a tendon) and is medically called lateral epicondylitis

Shoulder pain can be caused by: 

• Frozen shoulder — the medical name for this is adhesive capsulitis
• Rotator cuff disorders 

Ankle pain can be caused by a sprain or broken ankle.

Less common causes of joint pain affecting multiple joints

• Behçet's syndrome — a rare condition that causes inflammation of your blood vessels
• Cancer 
• Henoch-Schönlein purpura — a rare condition that causes inflammation of your blood vessels and usually affects children
• Hypertrophic pulmonary osteoarthropathy — a rare condition that causes clubbing of the fingers, which occurs in people with lung cancer
• Rare types of arthritis eg ankylosing spondylitis, juvenile arthritis or reactive arthritis
• Sarcoidosis — a rare condition that causes the development of small patches of red, swollen tissue in your organs

Certain medications can also cause joint pain affecting multiple joints eg the antibiotic isoniazid, the high blood pressure medicine hydralazine and steroids.

Hip pain in children

If your child has hip pain, see your GP urgently. This could be harmless but it could also be a sign of a serious condition such as: 

• Developmental dysplasia of the hip — this affects children aged 0–3 years
• Perthes' disease — this usually affects children aged 4–8 years and is more common in boys
• Slipped capital femoral epiphysis — this usually affects boys aged 10–17 years

There are many other causes of joint pain. It's important to see your GP as soon as possible if your symptoms don't improve and are affecting your day-to-day life.

Your GP will ask you about your symptoms and how it's been affecting you. They'll carry out a physical examination, including asking you to perform some simple exercises involving the affected joints.

After this, your GP may refer you for more tests to investigate further and discover the cause of your joint pain, including:

• Blood tests
• Ultrasound scan
• MRI scan
• X-ray

Your doctor will recommend treatment depending on the cause of your joint pain. In some cases, resting, along with taking over-the-counter painkillers (if advised by your doctor), may be enough. This is usually effective for minor injuries, such as overuse, a sprain or strain, alongside applying an ice pack on the first day after the injury. This is not as effective for longer-term injuries but can provide temporary relief for those with joint pain caused by chronic conditions eg osteoarthritis. 

You may need to stop doing activities that make any pain worse, such as driving, long walks and/or sports, depending on which joint is affected. However, you should still remain active so the muscles around your affected joint do not weaken. 

Depending on your diagnosis, other joint pain treatments may be needed including:

• Joint injections
• Knee arthroscopy surgery
• Medication — this may include anti-inflammatories, drugs that specifically treat your condition or painkillers
• Physiotherapy

In cases where your joint is severely damaged, your doctor may recommend joint replacement.

The likely course of your joint pain will depend on the underlying cause. For many, the pain will resolve without any long-term problems. However, for others, long-term treatment may be needed and long-term problems may still occur, such as persistent discomfort or restricted movement of the affected joint.