In a case of eczema herpeticum presenting with umbilicated vesicles, what is the likely diagnosis?

In cases of eczema herpeticum, the presence of umbilicated vesicles is a hallmark sign associated with a herpes simplex virus infection. This condition arises when the herpes virus infects skin that is already affected by eczema, leading to the formation of clustered vesicles that eventually become crusted, ulcerated, or weeping. The umbilicated appearance of the vesicles, which can resemble small, dimpled disks, is characteristic of herpes infections.

The other conditions listed do not typically present with umbilicated vesicles. Basal cell carcinoma may appear as a pearly nodule but does not feature vesiculated lesions. Contact dermatitis presents with different types of lesions (erythematous and papular, rather than vesicular and umbilicated) that are confined to the area of contact with the allergen or irritant. Eczema (atopic dermatitis) itself can lead to various forms of skin lesions, but does not produce the specific umbilicated vesicles associated with herpes simplex virus infections.

Understanding this distinction is crucial for accurate diagnosis and treatment of the condition, emphasizing the importance of recognizing the clinical presentation in conjunction with the patient's history of atopic dermatitis.