What characteristic feature is associated with erythema multiforme?

Erythema multiforme is characterized by the presence of target or bull's eye lesions on the skin, which are distinctive for this condition. These lesions typically have a central area that appears darker, surrounded by a lighter ring, and then a red halo on the outside. This classic appearance is key to diagnosing erythema multiforme, as it visually differentiates it from other skin conditions.

In contrast, the other characteristics mentioned do not align with erythema multiforme. Scaling lesions are more indicative of conditions like psoriasis. Blistering on mucous membranes can occur in different diseases, such as pemphigus or mucous membrane pemphigoid, but is not a defining feature of erythema multiforme. Chronic red patches might be seen in conditions such as eczema or rosacea, but they lack the distinctive target lesions that are emblematic of erythema multiforme. Thus, the presence of target iris or bull's eye lesions is what accurately describes the hallmark of erythema multiforme.