Also classified as autoimmune disorders, inflammatory arthritis is a grouping of the types of arthritis involving the immune system. In autoimmune disorders, the body sends errant messages to cells with immune function, including white blood cells, instructing them to attack the body’s own tissues. The damaged tissues cause deformity, instability, and scarring within the joints. These diseases are characterized by the presence of white blood cells in the joint fluid.
One of the most common types of inflammatory arthritis is rheumatoid arthritis (also referred to as RA), affecting between 1 and 2 million Americans.1 It occurs most often in the hands, wrists and feet. Rheumatoid arthritis (RA) is a chronic inflammatory disease that affects the synovial lining between the joints and can lead to severe pain and loss of function.
The presence and severity of RA symptoms vary between individuals: some people develop severe, sudden pain while others have very mild symptoms. Onset of the disease is usually gradual, but symptoms may progress rapidly, so early diagnosis and treatment is crucial to limiting the scope of potential joint damage.
While the exact cause of rheumatoid arthritis is unknown, researchers believe a combination of genetic, environmental, and hormonal factors are to blame. RA is more common in women.
Rheumatoid arthritis can be a difficult disease to diagnose, requiring a combination of medical history, physical exam, laboratory testing, and imaging studies. Symptoms can be treated with various medications.2
Symptoms of inflammatory arthritis are not localized to the damaged joint: patients may also experience fever, weakness, and organ damage in addition to the stiffness and pain in the joints. Treatment is often conservative, including a combination of exercise programs to retain strength and mobility and medical therapies to help reduce inflammation and pain. Rarely do patients require surgery for these conditions.
Causes of inflammatory arthritis are generally unknown, though it is believed that genetic factors play a large role. There is also growing evidence that environmental factors such as viral infections can be a trigger for the condition.
One of the best-known diseases is gout, which is characterized by a painful accumulation of urate crystals in the joints. Gouty arthritis is caused by a metabolic abnormality, and is most common in the big toe, knee and wrist.3 Conditions closely resembling gout include:
- Saturnine gout
- Chondrocalcinosis (calcium pyrophosphate dihydrate deposition disease)
- Lesch-Nyhan syndrome
- Wilson disease
- Farber’s lipogranulomatosis
- Systemic lupus erythematosus (SLE)
- Neonatal lupus
- Subacute cutaneous lupus
- Drug-induced lupus
Additional groupings of inflammatory diseases are classified according to their mechanism of onset or site of action.
- Infectious arthritis encompasses a number of conditions caused by bacterial or viral infection, including rheumatic fever, Lyme disease, fungal arthritis, Fifth disease, tuberculosis arthritis, gonococcal arthritis, Cogan’s syndrome, Pott’s disease, spirochetal arthritis, and Sydenham’s chorea, among others. This category is sometimes referred to as “bacterial arthritis” or “septic arthritis.”3
- Spondyloarthropathies, including ankylosing spondylitis, are relatively rare and are believed to be driven by a strong genetic component. Other spondyloarthropathies include psoriatic arthritis, reactive arthritis, brucellar spondylitis, enteropathic arthritis, and sacroiliitis.4
- Vasculitis describes a damaging type of inflammation that affects the blood vessels and occurs in conditions such as Henoch-Schönlein purpura, Behcet’s disease, Takayasu’s arteritis, Wegener’s granulomatosis, and Churg-Strauss syndrome.
- Tendinitis describes a painful inflammation of the tendons attaching muscle to bone and occurs all over the body. Common sites of injury include the Achilles tendon, tibia, and rotator cuff.
- Bursitis is another painful condition caused by inflammation of synovial sacs in the joints. Common types include calcaneal bursitis, olecranon bursitis, prepatellar bursitis, and trochanteric bursitis.
- Hemorrhagic arthritis describes joint inflammation caused by bleeding within a joint.3
See symptoms and treatments for different types of bursitis in the Bursitis Health Center