Professional and Linguistic Assessments Board (PLAB) Practice Exam

Erythema multiforme is characterized by the presence of multiple target lesions on the skin, which are typically red or purplish rings surrounding a pale central area. These lesions can often be itchy, and they arise due to an immune response, commonly triggered by infections, especially herpes simplex virus, or certain medications. The distinct "target" appearance is a key hallmark of this condition, differentiating it from other skin disorders. In contrast, dermatitis herpetiformis typically presents with small, grouped vesicles and a more papular appearance rather than distinct target lesions. Urticaria, on the other hand, involves raised, itchy welts (hives) that come and go, lacking the stable target lesion morphology. Impetigo presents with vesicular or crusted lesions, usually in a honey-colored scale, and is primarily a bacterial infection rather than an immunological response, making it distinct from erythema multiforme. Understanding these characteristics helps identify erythema multiforme and its specific clinical presentation amidst other dermatological conditions.