“Hair-on-end” skull changes are typically seen in individuals suffering from thalassaemia. They are induced by widening of the diploic space due to marrow expansion that is a consequence of ineffective and excessive erythropoiesis. We present a child with severe congenital neutropenia who exhibited the typical hair-on-end sign on plain skull radiographs and MRI. In this patient the skull changes were very likely induced by the expansion of white blood cell precursors induced by long-term daily injections of recombinant human granulocyte colony stimulating factor (G-CSF) to treat his confounding disease. This case report is the first description of hair-on-end changes associated with the use of G-CSF.