What autoimmune diseases are associated with lupus?

Autoimmune Diseases Associated with Lupus

Patients with systemic lupus erythematosus (SLE) frequently develop other autoimmune conditions, with thyroid disorders being the most common (10.5%), followed by Sjögren's syndrome (2.8-7%), rheumatoid arthritis (0.4-4%), autoimmune hepatitis (2.2-4.7%), systemic sclerosis (0.2%), and inflammatory bowel disease. 1, 2, 3

Most Common Co-occurring Autoimmune Diseases

Autoimmune Thyroid Disease (Most Prevalent)

• Thyroid disorders represent the most frequent autoimmune comorbidity in SLE patients, affecting approximately 10.5% of cases 1
• Hashimoto's thyroiditis is more common than Graves' disease in this population 1, 3
• Regular thyroid function screening is warranted given this strong association 3

Sjögren's Syndrome

• Occurs in 2.8-7% of SLE patients, characterized by lymphocytic infiltration of lacrimal and salivary glands causing dry eyes and dry mouth 1, 2, 3
• Can present as secondary Sjögren's syndrome in the context of SLE 2, 3
• Patients have increased risk for lymphoproliferative disorders, with approximately 5% developing lymphoma 3
• Co-management with rheumatology is essential due to potential systemic complications 3

Rheumatoid Arthritis

• Develops in approximately 0.4-4% of SLE patients 1
• More commonly occurs in older SLE patients compared to younger patients 1
• Immunosuppressive therapy benefits both conditions and prevents joint deformity 1

Autoimmune Hepatitis (AIH)

• Approximately 2.2-2.8% of SLE patients develop AIH, while conversely 2.7-4.7% of AIH patients have concurrent SLE 1
• SLE patients with elevated liver enzymes should be evaluated for AIH, as 19.4% of those with hepatic abnormalities have concurrent AIH 1
• Patients with both conditions demonstrate higher IgG levels and may have worse prognosis 1
• Complications can include myocarditis and thrombotic thrombocytopenic purpura 1

Systemic Sclerosis (Scleroderma)

• Occurs in approximately 0.2% of SLE patients 1
• When present, particularly in juvenile-onset scleroderma, pulmonary arterial hypertension can develop in <10% of cases before age 21, though it can be fatal when it occurs 1
• Primary biliary cholangitis occurs in 8% of limited cutaneous systemic sclerosis cases 3

Inflammatory Bowel Disease

• IBD occurs in 2-11.4% of SLE patients, with ulcerative colitis being more common than Crohn's disease 1
• Conversely, 3.7-11.4% of IBD patients develop SLE 1

Clinical Implications and Monitoring

Screening Recommendations

• Patients with SLE should be monitored for development of additional autoimmune disorders, particularly thyroid disease, Sjögren's syndrome, and rheumatoid arthritis 2, 3
• Antinuclear antibody profiles and specific autoantibodies should be assessed at baseline and when new symptoms emerge 2
• Regular assessment for dry eyes, dry mouth, joint symptoms, and thyroid dysfunction is warranted 3

Important Clinical Pitfalls

• The presence of one autoimmune condition substantially increases risk for others—this is termed the "kaleidoscope of autoimmunity" 4
• Autoimmune diseases share genetic backgrounds, particularly within the major histocompatibility complex, explaining their clustering 4
• Environmental triggers (drugs, viral infections, UV radiation) can precipitate multiple autoimmune conditions in genetically susceptible individuals 4
• Complement deficiencies can present with lupus-like disease, highlighting the complex relationship between immunodeficiency and autoimmunity 2

Management Considerations

• Immunosuppressive therapy used for SLE often benefits concurrent autoimmune conditions 1
• Hydroxychloroquine remains standard of care for SLE and may provide benefit for associated autoimmune manifestations 5, 6
• When multiple autoimmune conditions coexist, treatment must balance disease control across all affected systems while minimizing cumulative immunosuppression-related complications 1
• Patients with primary immunodeficiencies like selective IgA deficiency have increased risk of developing autoimmune conditions and require appropriate screening 2