Ease Into Prep with a PANCE^® Question of the Day

The correct answer is E. Young to middle-aged women are predominantly affected with systemic lupus erythematosus, showing a wide range of signs and symptoms. Skin involvement occurs in 80% of cases and is likely to be very helpful in making the correct diagnosis. Of all the serologic tests, anti-Smith antibodies carry the highest specificity for lupus erythematosus.

Anticentromere antibodies (choice A) are sensitive and specific for CREST syndrome, a variant of systemic scleroderma that is characterized by calcinosis cutis, Raynaud phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasias. Antinuclear antibodies are also positive in 90% of these patients. Due to their high degree of sensitivity, antinuclear antibodies are used as the screening test for lupus.

Antihistone antibodies (choice B) are formed in drug-induced lupus erythematosus. They are highly specific for this disease and impose a homogenous pattern of antinuclear antibody staining. Procainamide, methyldopa, and hydralazine are the offending agents most commonly encountered as culprits of drug-induced lupus.

Anti-Jo-1 antibodies (choice C) are a marker of dermatomyositis with significant muscle involvement. They can also be detected in patients who have myositis in the absence of skin disease.

Anti-Ro antibodies (choice D) are detected in subacute cutaneous lupus erythematosus, neonatal lupus erythematosus, and Sjogren syndrome, and should be valued in the context of clinicopathologic correlation.

PEARL: The screening test for SLE is the antinuclear antibody, which is seen in practically all patients who have SLE. Specific tests that are used as confirmatory tests include double-stranded DNA and anti-Smith antibodies.