Systemic Lupus Erythematosus (SLE) is a chronic autoimmune condition where the immune system mistakenly attacks healthy tissues and organs. Tendonitis is the inflammation of a tendon, the fibrous cord connecting muscle to bone. Lupus can cause tendonitis, but the inflammation often specifically affects the tendon sheath, a condition known as tenosynovitis. This inflammatory involvement of tissues surrounding the joints is a recognized manifestation of SLE.
Lupus and Musculoskeletal Involvement
Musculoskeletal pain is one of the most common complaints for individuals diagnosed with SLE. Lupus is a systemic disease, meaning it targets connective tissues, joints, and surrounding structures throughout the body. This broad involvement explains why pain can originate from various sources, including the joints or nearby soft tissues like muscles and tendons.
The most prevalent issues are arthralgia (joint pain without swelling) and arthritis (inflammatory joint swelling). Lupus-related arthritis is typically non-erosive, rarely causing the permanent bone damage seen in other inflammatory conditions. SLE’s propensity to inflame the joint lining (synovium) and structures enabling joint movement naturally places tendons at risk for inflammation.
Specific Mechanisms of Tendon Inflammation in Lupus
Lupus-related tendon inflammation occurs because the systemic autoimmune process targets the tendon’s protective covering. The tendon sheath contains a synovial membrane, which is structurally similar to the joint lining, making it a target for the same inflammatory attacks that cause arthritis.
The inflammation is driven by the deposition of immune complexes—clusters of antibodies bound to self-antigens—within the tendon sheath. These complexes activate the complement system and trigger the release of pro-inflammatory cytokines, initiating an inflammatory cascade. This chronic inflammation damages the synovial membrane, causing the pain and swelling characteristic of tenosynovitis. Common areas affected include the wrists, hands (sometimes called flexor tenosynovitis), ankles, shoulders, and elbows.
Distinguishing Lupus-Related Tendon Pain from Overuse Injuries
Differentiating between autoimmune-driven tendon pain and pain caused by mechanical strain or overuse is essential for diagnosis. Pain from lupus-related tenosynovitis is frequently symmetrical, affecting the same tendon groups on both sides of the body, such as both wrists or ankles.
This inflammatory pain may involve multiple sites simultaneously and can have a migratory quality, moving from one location to another. Lupus-related tendon pain is commonly accompanied by other systemic symptoms, such as fatigue, fever, or skin rashes, indicating an underlying disease flare. In contrast, mechanical tendonitis is typically localized to a single, unilateral site and has a clear relationship to repetitive activity or recent physical strain.
Management and Treatment Approaches
Effective management of lupus-related tendon inflammation requires treating the underlying systemic autoimmune disease, not just the local symptom. Unlike typical overuse injuries, which respond primarily to rest and local anti-inflammatories, the primary goal is controlling SLE activity. Systemic medications are the foundation of therapy for lupus tenosynovitis.
Nonsteroidal anti-inflammatory drugs (NSAIDs) and low-dose corticosteroids are often used initially to control pain and reduce inflammation. For long-term control, disease-modifying antirheumatic drugs (DMARDs), such as hydroxychloroquine or methotrexate, are essential to modulate the immune response. Localized treatments, including rest, physical therapy, or corticosteroid injections into the tendon sheath, may be used as an adjunct for symptomatic relief.