Langerhans Cell Histiocytosis Mimicking Prurigo Nodularis

Langerhans cell histiocytosis (LCH) depicts a rare disease belonging to the group of histiocytoses. The disease is based on a clonal expansion of myeloid precursors. Frequently, gain-of-function mutation in the MAPK signaling pathway can be detected. In 2016, Emile et al. proposed a revised classification of histiocytoses and neoplasms of the macrophage-dendritic cell lineages categorizing LCH together with Erdheim-Chester disease (ECD), indeterminate cell histiocytosis and mixed LCH/ECD in the L (Langerhans cell) group.