Professional and Linguistic Assessments Board (PLAB) Practice Exam

Which type of rash is characterized by the absence of blisters and appears particularly on the abdomen of pregnant women?

1. Pemphigoid gestationis

2. Cholestasis rash

3. Polymorphic eruption of pregnancy

4. Dermatitis herpetiformis

The correct answer is: Polymorphic eruption of pregnancy

The polymorphic eruption of pregnancy is characterized by its typical presentation as a pruritic, erythematous rash that usually appears on the abdomen, but can also spread to the trunk and limbs. It typically does not form blisters, which sets it apart from other rashes that do have vesicular components, such as pemphigoid gestationis and dermatitis herpetiformis. This rash usually arises in the late second or third trimester and resolves after delivery. It may be associated with stretch marks or changes in the skin due to pregnancy. The lack of blisters is a defining feature, and the eruption generally causes significant itching, which can be distressing for the affected women. In contrast, pemphigoid gestationis is characterized by blister formation and is an autoimmune condition. Cholestasis rash is related to liver function and usually presents with intense itching, often without a rash, and it may be seen in conjunction with jaundice. Dermatitis herpetiformis, while pruritic and blistering, is also an autoimmune condition linked to gluten sensitivity and is not specific to pregnancy. The understanding of these distinctions is crucial for correctly identifying conditions based on their presentations during pregnancy.