Generalized eruptive histiocytosis (GEH; also known as generalized eruptive histiocytoma) is a very rare form of non-Langerhans cell histiocytosis (non-LCH). It is usually a benign, self-limited condition that presents as multiple, asymptomatic, discrete red-brown papules located symmetrically on the face, trunk, and extremities. Successive crops of lesions erupt over years with eventual spontaneous resolution.

In a review of 25 cases of GEH, the mean age of onset for adults was 54 years, with onset ages ranging from 23-84 years. The mean age of onset for children was 4 years, with onset ages ranging from 10 months to 10 years. Males represented 57% of all cases that were reviewed.

The etiology of GEH is unknown. There are reports of GEH transforming into another subtype of non-LCH, such as xanthoma disseminatum, raising the question of whether GEH is actually an early phase of a more mature non-LCH.

GEH has been rarely reported to be associated with malignant hematologic disorders of myeloid lineages. As such, it is important to thoroughly screen GEH patients for associated hematologic malignancies.