Differential Diagnosis for Systemic Lupus Erythematosus (SLE)

Approach from Emergency Department (ED) to Diagnosis and Treatment

• Single Most Likely Diagnosis

  • Systemic Lupus Erythematosus (SLE): Given the question's context, SLE is the primary condition being considered. It's a chronic autoimmune disease that can affect various parts of the body, including the skin, joints, kidneys, brain, and other organs. Symptoms can be diverse and nonspecific, making diagnosis challenging but essential for appropriate management.

• Other Likely Diagnoses

  • Rheumatoid Arthritis (RA): This autoimmune disorder primarily affects the joints, causing inflammation and pain. While its presentation can overlap with SLE, the pattern of joint involvement and the presence of specific autoantibodies can help differentiate between the two.
  • Sjögren's Syndrome: An autoimmune disorder characterized by its effects on exocrine glands, particularly the salivary and lacrimal glands, leading to dry mouth and eyes. It can occur alone or in association with other autoimmune diseases like SLE.
  • Mixed Connective Tissue Disease (MCTD): A condition that combines features of lupus, scleroderma, and rheumatoid arthritis. Patients may exhibit a variety of symptoms, including joint pain, muscle weakness, and skin changes.

• Do Not Miss Diagnoses

  • Antiphospholipid Syndrome (APS): This condition is characterized by the presence of antiphospholipid antibodies, which can lead to blood clots in arteries or veins. It can occur in isolation or in association with SLE and is critical to diagnose due to its risk of causing strokes, heart attacks, and other thrombotic events.
  • Vasculitis: Inflammation of the blood vessels, which can be associated with various autoimmune diseases, including SLE. Prompt recognition and treatment are essential to prevent organ damage.
  • Infectious Diseases (e.g., Endocarditis, Tuberculosis): These conditions can mimic SLE in their presentation and must be ruled out, especially in patients with fever, weight loss, or other systemic symptoms.

• Rare Diagnoses

  • Scleroderma (Systemic Sclerosis): A chronic disease characterized by deposition of collagen, leading to thickening of the skin and involvement of internal organs. While it shares some features with SLE, its distinct skin and organ manifestations set it apart.
  • Relapsing Polychondritis: A rare autoimmune disorder involving cartilaginous structures, leading to recurrent episodes of cartilage inflammation. It can affect the ears, nose, trachea, and joints, among other areas.
  • Ehlers-Danlos Syndrome: A group of disorders that affect connective tissues supporting the skin, bones, blood vessels, and many other organs and tissues. Its presentation can sometimes overlap with that of SLE, particularly in terms of joint hypermobility and skin manifestations.