Filgrastim-induced cutaneous vasculitis in a patient undergoing stem cell mobilization

Abstract: Neupogen (filgrastim), a granulocyte colony-stimulating factor, is widely utilized for the management of chemotherapy-induced neutropenia and as part of mobilization regimens for hematopoietic stem cell transplantation. Filgrastim-induced cutaneous vasculitis (CV) is a rare adverse event. This case report details a patient at a bone marrow transplantation center diagnosed with Hodgkin lymphoma who received gemcitabine, dexamethasone, and cisplatin (GDP) chemotherapy as a mobilization regimen. The course of chemotherapy was uneventful. On day 9 postchemotherapy, filgrastim was initiated to mobilize stem cells. By day 2 of filgrastim administration, the patient developed a severe rash and pruritus. After thorough evaluation and exclusion of other potential causes, the rash was attributed to filgrastim-induced CV, as the patient was not receiving any other medications that could account for this reaction. While low-dose systemic corticosteroids are typically recommended for treating this condition, filgrastim was continued for an additional 3 days to complete stem cell mobilization. The patient was managed with diphenhydramine (1 ampoule three times daily) for symptomatic relief, and the rash resolved gradually following the discontinuation of filgrastim, without the need for corticosteroid therapy. Filgrastim is generally well tolerated, with common side effects including bone pain, nausea, vomiting, diarrhea, fever, and headache. However, rare but serious adverse effects, such as splenic rupture, pulmonary toxicity (particularly in combination with other drugs causing similar effects), arterial thrombosis, and CV, have been reported postmarketing. This case highlights the importance of recognizing and managing rare adverse events associated with filgrastim.