RESUMO
Atopic dermatitis (AD) has become a global health concern due to an increase in its frequency over the past few decades. This illness not only reduces the quality of life but also imposes a considerable financial burden due to the increased risk of skin infections. This case report explores the presentation of a four-month-old male infant with a personal history of atopic dermatitis that developed yellow scaly lesions on the scalp, which were assumed to be cradle cap. However, there was a clinical worsening of the cutaneous lesions, with the appearance of vesicles, so he was referred to the Pediatric Emergency Room after an urgent dermatology appointment. A blood test was performed, which revealed severe eosinophilia and a slightly increased total IgE. Considering the patient's past medical record of atopic dermatitis and the observable characteristics of the skin rash, there was a strong suspicion of eczema herpeticum (EH). Consequently, intravenous acyclovir treatment was initiated, along with an antibiotic, as there were concerns about a potential secondary infection. He was followed up with a pediatric and dermatology appointment, with a resolution of skin lesions after six weeks. EH is a rare clinical entity, usually caused by herpes simplex virus (HSV) types 1 and 2. It is a clinical entity that, while being uncommon, is one of the few dermatological emergencies responsible for a high morbidity rate, associated with the systemic spread of the viral infection.