Professional and Linguistic Assessments Board (PLAB) Practice Exam

What target lesion is most commonly associated with Lyme disease?

1. E. marginatum

2. E. chronicum migrans

3. Necrobiosis lipoidica

4. Psoriasis

The correct answer is: E. chronicum migrans

The target lesion most commonly associated with Lyme disease is erythema chronicum migrans. This characteristic rash typically appears as a circular, red area that expands outward, often with a central clearing, giving it a "bull's-eye" appearance. It usually develops at the site of a tick bite and is one of the early signs of Lyme disease, which is caused by the Borrelia bacterium transmitted through tick bites. Erythema chronicum migrans is significant in the diagnosis of Lyme disease because recognizing this specific lesion can prompt timely treatment and prevent the progression of the disease into more severe stages, which may involve neurological or cardiac complications. Knowing this clinical presentation is crucial for healthcare providers who are assessing potential Lyme disease cases in patients who have been exposed to tick habitats. The other options provided do not typically present as lesions associated with Lyme disease. Erythema marginatum, for example, is more commonly associated with rheumatic fever, while necrobiosis lipoidica and psoriasis have distinct clinical features that do not overlap with the typical characteristics of Lyme disease lesions.