A 29-year-old African American woman presents to her primary care physician complaining of ankle pain that she attributes to “arthritis” and a nonpruritic rash on her shins that both began approximately 6 days earlier. She has no history of arthritic complaints. Her temperature is normal and she has no chills, is not nauseated, and has not vomited. She has no abdominal or chest pain and is not short of breath. She has not noticed any change in skin color or in the color of her urine.
She works as an administrative secretary. She is not married but dates regularly. She is sexually active and says she practices “safe sex.” Her menstrual periods are regular and she has no vaginal discharge. She knows of no illnesses or similar symptoms among friends or family. She takes no medications, does not smoke cigarettes, and does not use illicit drugs. She drinks alcohol socially. She has not traveled outside the United States.
Physical examination reveals mild erythema, swelling, and tenderness in both ankles and red nodular lesions on the anterior tibial surfaces. Results of chest, abdominal, and pelvic examinations are normal.
What diagnostic clues do the history, physical examination, and labs offer, and which of the following tests would you order to help make a diagnosis?
A. Hepatitis serology
B. ASO titer
C. Rheumatoid factor serology
D. Culture for gonoccocus
E. Radiograph of the chest