Professional and Linguistic Assessments Board (PLAB) Practice Exam

Which condition presents with a scaly rash on the peri-orbital and nasolabial regions associated with dandruff?

1. Seborrhoeic dermatitis

2. Psoriasis

3. Pityriasis rosea

4. Eczema herpeticum

The correct answer is: Seborrhoeic dermatitis

Seborrhoeic dermatitis is characterized by the presence of a scaly rash that commonly affects the scalp (leading to dandruff) as well as other oily areas of the body, including the face. The peri-orbital (around the eyes) and nasolabial (around the mouth) regions are typical sites where this condition can manifest, often appearing as a red, flaky rash with associated greasy scales. This condition is thought to be linked to sebaceous gland activity and the overgrowth of Malassezia yeast on the skin, both of which are commonly found in areas with more oil production. The association with dandruff is a key feature; in fact, seborrhoeic dermatitis of the scalp is often referred to as dandruff when it is mild. Thus, when considering the presentation of a scaly rash in the specified facial areas along with dandruff, seborrhoeic dermatitis stands out as the accurate diagnosis. Other conditions have different characteristics: psoriasis tends to present with more defined, thick, silvery scales, and usually on extensor surfaces; pityriasis rosea tends to display a herald patch followed by concentric lesions; and eczema herpeticum arises from herpes simplex virus infection superimposed on atopic dermatitis,