What characteristic rash is indicative of erythema multiforme?

The characteristic rash indicative of erythema multiforme is indeed the maculopapular lesions that can progress to target lesions or iris lesions, which are key identifiers of this condition. Erythema multiforme is typically associated with various stimuli, including infections, medications, and other triggers. The lesions often appear abruptly and are most commonly found on the extremities, particularly on the palms and soles, as well as on mucosal surfaces.

When examining the other options, erythema marginatum is a type of rash associated with rheumatic fever, and it has a distinct morphology that differs from the target lesions of erythema multiforme. Varicella, commonly known as chickenpox, presents with vesicular lesions that are grouped and itchy, which do not resemble the lesions seen in erythema multiforme. Impetigo, a bacterial skin infection, usually presents with crusting and honey-colored lesions, also differing significantly from the typical target lesions characteristic of erythema multiforme.

Thus, the identification of the target lesions aligns specifically with erythema multiforme, confirming its presentation as the correct answer to the question.