Question

Enumerate differences between drug-induced lupus and systemic lupus erythematosus.

Hint:

The key differences between drug-induced lupus and systemic lupus erythematosus lie in the cause (drug-induced versus autoimmune) and the severity and chronicity of the disease.

Answer 1

Step 1: Difference in Etiology.
- Drug-Induced Lupus (DIL): Triggered by medications like hydralazine, procainamide, and isoniazid. It is reversible upon discontinuation of the drug.
- Systemic Lupus Erythematosus (SLE): An autoimmune disease with no identifiable external cause. SLE is chronic and requires long-term management.
Step 2: Antibodies Present.
- DIL: The hallmark antibody is anti-histone, which is often present in high titers.
- SLE: Multiple autoantibodies are involved, including anti-dsDNA, anti-Smith, and anti-RNP, which are more specific for SLE.
Step 3: Clinical Manifestations.
- DIL: Clinical manifestations are generally milder and include arthritis, rash, and fatigue. Renal and central nervous system (CNS) involvement is rare.
- SLE: SLE can affect multiple organs, including the kidneys (lupus nephritis), CNS, and the heart, and is associated with more severe symptoms.
Step 4: Resolution of Disease.
- DIL: The disease usually resolves after stopping the causative drug.
- SLE: SLE is a lifelong condition that requires immunosuppressive therapy to control symptoms.