Unusual Presentations of Systemic Lupus Erythematosus: A Narrative Review

Systemic lupus erythematosus (SLE) is a chronic systemic autoimmune disease characterized by an almost 10:1 female predominance, the presence of deleterious nuclear autoantibodies, a tendency for flare, and striking protean manifestations. Early diagnosis is associated with less damage accrual, lower costs, and improved quality of life due to timely treatment. However, early disease may not uncommonly show nonspecific presentation, a single classification criterion, or an unusual organ involvement contributing to frequent, often substantial diagnostic delays. We reviewed the literature (1982-2022) to accumulate and classify all reports of rare, atypical, and unusual presentations. These can involve almost every organ and system, and thus, present to physicians in every discipline and setting. Increasing physicians' awareness of the potential of occult SLE to appear in varied, diverse, and unexpected presentations, may encourage the inclusion of SLE in the differential. Informed history and examination focusing on systemic and joint symptoms and mucocutaneous involvement, and basic tests (focusing on leukopenia, thrombocytopenia, and proteinuria; followed by antinuclear antibodies and complement levels) will correctly diagnose most patients on presentation or within the following months and enable timely treatment.