RA is a chronic inflammatory disorder primarily known for causing pain, swelling, and stiffness in the joints, particularly the hands, wrists, and feet. However, RA is fundamentally a systemic autoimmune disease, meaning it affects the entire body. The chronic inflammation that attacks the joint lining can extend to other tissues and organs. This leads to a range of extra-articular, or non-joint, symptoms that are often less recognized but can be serious.
Skin and Subcutaneous Manifestations
The skin and subcutaneous tissue are common sites for extra-articular involvement. Rheumatoid nodules are the most frequent physical finding, appearing as firm, non-tender lumps in approximately 20% to 30% of people with RA. They typically appear over bony prominences or areas of constant pressure, such as the elbows, forearms, and Achilles tendons. Their presence often indicates a more active or severe form of RA and is associated with higher levels of the rheumatoid factor autoantibody.
Another, more serious skin manifestation is rheumatoid vasculitis, which involves inflammation of the small and medium-sized blood vessels. This inflammation restricts blood flow to tissues, causing symptoms like small skin ulcers or purple-red rashes (palpable purpura), especially on the legs. Severe cases can lead to small areas of tissue death (infarcts) around the nail folds or fingertips due to reduced blood supply.
Ocular and Oral Involvement
The eyes can become targets of systemic inflammation, ranging from mild irritation to vision-threatening conditions. The most frequent complaint is severe dryness, known as keratoconjunctivitis sicca, often linked to secondary Sjögren’s Syndrome. This occurs when the immune system attacks the tear and saliva-producing glands, causing a persistent lack of moisture in the eyes and mouth. The dryness can lead to a gritty sensation, light sensitivity, and corneal damage.
A more concerning ocular symptom is scleritis, the painful inflammation of the sclera (the tough, white outer layer of the eyeball). Scleritis causes intense, deep eye pain and the eye appears dusky red or purplish. A milder form, episcleritis, involves inflammation of the thin layer just above the sclera, presenting as a temporary, red patch that is usually less painful. Scleritis is associated with more aggressive RA and an increased risk of systemic vasculitis.
Respiratory and Cardiac System Effects
The lungs and heart are internal organs where RA-related inflammation can have profound consequences. Interstitial Lung Disease (ILD) is a common pulmonary complication where chronic inflammation causes scarring (fibrosis) in the lung tissue. This progressive scarring makes the lungs stiff, leading to symptoms like shortness of breath and a persistent, dry cough. Another condition is pleuritis, the inflammation of the pleura lining the lungs, which causes sharp chest pain when breathing deeply.
The systemic nature of RA significantly increases the risk of cardiovascular disease, which is the leading cause of death in people with the condition. Chronic inflammation drives this heightened risk by accelerating atherosclerosis (the hardening and narrowing of the arteries). Inflammation promotes the formation and instability of arterial plaques. It can also directly affect the heart sac, causing pericarditis, an inflammation of the lining around the heart that leads to chest pain.
Neurological and Hematological Symptoms
The nerves and the blood are two systems where RA’s systemic effects can manifest. Neurological involvement often includes compression neuropathies, such as Carpal Tunnel Syndrome, which results from inflamed wrist joints pressing on the median nerve. This causes numbness, tingling, and pain in the hand and fingers. Peripheral neuropathy can also occur when inflammation directly damages small nerves, leading to symmetrical numbness, tingling, or a burning sensation, most often starting in the feet.
Hematological (blood-related) issues are also common, such as Anemia of Chronic Disease (ACD), which affects many patients with active RA. In ACD, inflammatory proteins interfere with the body’s ability to utilize iron for red blood cell production, despite adequate iron stores. This results in fewer oxygen-carrying red blood cells. A rare but serious complication is Felty’s Syndrome, characterized by long-standing RA, an enlarged spleen (splenomegaly), and a dangerously low white blood cell count (neutropenia).