Which symptom is characteristic of eczema herpeticum?

Eczema herpeticum is a viral skin infection caused by the herpes simplex virus that occurs in individuals with atopic dermatitis (eczema). A hallmark symptom of eczema herpeticum is the presence of umbilicated vesicles. These vesicles resemble small blisters that have a depressed center, often described as ‘umbilicated.’ They typically arise in areas of the skin that are already affected by eczema, and the rapid onset often follows a period of irritation or an outbreak of eczema.

In contrast, the other options are associated with different dermatological conditions or manifestations. Scaly patches are more characteristic of conditions like psoriasis or chronic dermatitis. Exudate formation may occur in various infections or inflammatory skin conditions but is not specific to eczema herpeticum. Crusting lesions might develop in response to significant exudation or secondary infections but are not a defining feature of the umbilicated vesicles that characterize the herpes infection in this context. Hence, umbilicated vesicles stand out as the most distinctive symptom for diagnosing eczema herpeticum.