Subcutaneous Thrombotic Vasculopathy with Features of Leukocytoclastic Vasculitis Following Intravenous Injection of Crushed Oxycodone and Methylphenidate Tablets: A Case Report with Literature Review.

Subcutaneous thrombotic vasculopathy (STV) is a rare, non-inflammatory occlusive disorder of the cutaneous microvasculature that predominantly involves the subcutaneous tissue and may closely mimic inflammatory vasculitis. We describe a case of STV with overlapping features of leukocytoclastic vasculitis (LCV) in a 23-year-old woman presenting with rapidly progressive, painful purpuric skin lesions. The patient had a history of polysubstance use disorder and reported intravenous injection of crushed oral oxycodone and methylphenidate tablets. Histopathological examination of a deep skin biopsy revealed fibrin-rich thrombi occluding small vessels of the dermis and subcutaneous tissue. Fine granular IgA deposits in the walls of numerous superficial dermal blood vessels shown using direct immunofluorescence suggested LCV. Overall, the findings supported a mixed thrombotic-inflammatory vasculopathy with predominant features of STV. This case highlights the diagnostic complexity of STV and may suggest intravenous injection of crushed oral medications as a potential trigger through particle-induced microvascular obstruction and secondary thrombosis. In addition, we conducted a literature review indicating that STV remains a rare and likely underrecognized entity, with only a limited number of reported cases.