Joint pain

Joint pain (arthralgia): Causes and mechanisms

Joint pain, or arthralgia, is a symptom characterized by discomfort, a dull or sharp pain in one or several joints. It is important to distinguish arthralgia (subjective feeling of pain) from arthritis (objective signs of joint inflammation such as swelling, redness, limited movement). Joint pain can be caused by a wide range of factors, from age‑related changes to systemic autoimmune diseases.

Most common causes of joint pain

• Arthritides:
  • Osteoarthritis (arthrosis): A degenerative disease associated with wear of the joint cartilage. It most often affects the knee, hip and hand joints. Pain usually worsens with load and eases at rest.
  • Rheumatoid arthritis: An autoimmune disease in which the immune system attacks the body's own joints, causing chronic inflammation, pain, swelling and progressive deformation. Morning stiffness is characteristic.
  • Reactive arthritis: Inflammation of the joints that develops after a preceding infection (usually gastrointestinal or genitourinary).
• Injuries: Sprains, dislocations, fractures.
• Viral infections: Many viruses, including the influenza virus, can cause temporary joint pain similar to muscle pain (“myalgia”).
• Metabolic disorders: For example, gout, in which uric acid crystals deposit in the joints.

Joint pain in special populations

In certain population groups joint pain has specific causes. For example, in pregnant women it is often related to the action of the hormone relaxin and weight gain, as described in the article "Joint pain during pregnancy". If the pain is prolonged and does not resolve, it is classified as chronic pain.