Problem:
A 20-year-old man who is sexually active and runs track for his college presents to the clinic with complaints of an erythemic, pruritic rash on his groin and bilateral thighs. On exam, the clinician notes an erythemic scaly rash on his bilateral upper thighs and suprapubic region. The patient's penis and scrotum are unaffected. Which of the following should the clinician order to confirm the diagnosis? Nontreponemal antibody test Nucleic acid amplification technique Potassium hydroxide preparation Tzanck test