We report on a preterm infant (33rd gestational week) with a varicella-like congenital rash, which initially appeared to respond to therapy with acyclovir. At the age of 3 weeks, lesions were in different stages of evolution and still resembled a varicella zoster virus (VZV) infection. However, since proof of VZV infection was lacking and new lesions erupted at the age of 4 weeks, a skin biopsy was performed which revealed a diagnosis of Langerhans cells histiocytosis. Therapy with prednisone resulted in prompt healing of the lesions.
Discussion: Congenital Langerhans cell histiocytosis is rare and symptoms may vary substantially from case to case. Like in our observation it may be confused with congenital varicella. In case of congenital skin lesions of uncertain etiology a skin biopsy should be performed.