Description

• Multisystem autoimmune inflammatory disorder with variable presentation, disease course, and prognosis
• Can manifest in any organ system, especially dermatologic, renal, hematologic, musculoskeletal, and cardiovascular
• Synonyms: lupus, systemic lupus erythematosus (SLE)

Epidemiology

Incidence

• 5 to 7 per 100,000 person-years in United States
• Significant variation based on ethnicity: black, 16.0; American Indian/Alaska Native, 7.4; Hispanic, 5.6; Asian/Pacific Islander, 4.6; and white, 3.3 per 100,000 person-years
• Strong female predominance compared to male: 9.8 versus 0.8 per 100,000 person-years (~12-fold higher)
• Peak incidence: 3rd to 7th decades of life for females and 5th to 7th decades of life for males

Prevalence

• Ranges from 70 to 100 cases per 100,000 people in United States.
• Strong female predominance compared to male: 179 versus 21 cases per 100,000 people (~9-fold higher) with highest prevalence in black women: 498 cases per 100,000 people

Etiology and Pathophysiology

Genetic, environmental, immunoregulatory, hormonal, and epigenetic factors all play a role.

Genetics
>90 susceptibility loci for SLE in genome-wide association studies (1)[C]

Risk Factors

• Ethnicity: highest risk in black populations; intermediate risk in Asian, Hispanic, and American Indian/Alaska Native populations
• Hormonal: female sex, early menarche/menopause, endometriosis, surgical menopause
• Family history of SLE or autoimmune disease
• Environmental: cigarette smoking, crystalline silica exposure, exogenous female hormones, certain medications (drug-induced lupus)

Commonly Associated Conditions

Antiphospholipid syndrome, depression, fibromyalgia, thyroid disease, connective tissue disease syndromes (such as rheumatoid arthritis, Sjögren syndrome, systemic sclerosis)