Exploring the differential diagnosis of hemorrhagic vesicopustules in a newborn.

Hemorrhagic vesicles in a newborn present a challenging differential diagnosis including both infectious and neoplastic disorders. Patients should be evaluated in an efficient manner to arrive at the correct diagnosis as quickly as possible. We present here an interesting case that outlines the methodical workup that ultimately revealed the diagnosis of congenital Langerhans cell histiocytosis. After a diagnosis of Langerhans cell histiocytosis is made, it is important to evaluate the patient thoroughly for systemic involvement. Historically, the diagnosis of congenital self-healing Langerhans cell histiocytosis was used to delineate a benign self-limited disorder limited to the skin with spontaneous resolution during the first several months of life; this disorder may also be referred to as "self-regressive Langerhans cell histiocytosis." However, some newborns with initial skin-only Langerhans cell histiocytosis progress to have multisystem disease after spontaneous resolution has occurred. For this reason, the nomenclature is changing. We suggest using the term "skin-only Langerhans cell histiocytosis." Periodic long-term follow-up is recommended to monitor for relapse or progression to systemic disease.