Professional and Linguistic Assessments Board (PLAB) Practice Exam

What condition is characterized by shiny, painless areas of yellow/red skin, typically on the shin of diabetics?

1. Lichen planus

2. Necrobiosis lipoidica

3. Lichen sclerosis

4. Ebstein's anomaly

The correct answer is: Necrobiosis lipoidica

The condition characterized by shiny, painless areas of yellow/red skin, typically observed on the shins of diabetics, is necrobiosis lipoidica. This dermatological manifestation is often associated with diabetes mellitus and presents as localized patches that can appear atrophic and have a waxy texture. It may potentially indicate underlying vascular changes associated with diabetes. The other conditions mentioned are not characterized by the same presentation. Lichen planus primarily involves pruritic, polygonal papules and plaques that can be violaceous in color, often seen on the wrists or oral mucosa. Lichen sclerosis typically affects the genital area and reveals white patches of skin that may be itchy or painful. Ebstein's anomaly, fundamentally related to a congenital heart defect, bears no relation to skin findings. Thus, necrobiosis lipoidica is accurately identified due to its specific presentation and prevalence among diabetic patients.