While both cause a morbilliform rash, GVHD is distinguished by its typical onset after a stem cell or bone marrow transplant and its tendency to start on palms, soles, and ears.
This is a painful erythema, especially on hands and feet, directly related to the timing of a chemotherapy infusion, whereas GVHD has a more delayed and immunologic onset.
A viral cause is suggested by a prodrome of fever and URI symptoms before the rash, whereas GVHD follows the specific timeline of transplantation.
This reaction is strictly confined to sun-exposed areas and is linked to voriconazole use, unlike the more generalized rash of GVHD that can affect any site.
