Wound Characteristics Among Patients Exposed to Xylazine.

Importance: The alpha-2 agonist xylazine is increasingly detected as an adulterant in illicitly manufactured fentanyl. There is concern that xylazine may be responsible for an emerging pattern of necrotizing wounds among people who use drugs, but the clinical features of wounds associated with xylazine remain poorly characterized.

Objective: To systematically characterize the location, wound bed surface, and chronicity of wounds among persons with confirmed xylazine exposure.

Design, setting, and participants: This case series at 3 academic medical hospitals in Philadelphia, Pennsylvania, included patients with emergency department or inpatient encounters from April 2022 to February 2023 who had a wound-related chief complaint and xylazine detected with urine gas chromatography-mass spectroscopy.

Exposure: Xylazine.

Main outcomes and measures: The location, size, wound bed, and chronicity of wounds associated with xylazine using electronic medical record abstraction and Fisher exact tests.

Results: Of 59 wounds from 29 unique patients with confirmed xylazine exposure (mean [SD] age, 39.4 [8.8] years; 15 [52%] male; all using fentanyl, and 23 [79%] routinely injecting opioids), 53 wounds (90%) were located on extremities, and 41 (69%) involved extensor surfaces. Five wounds (9%) involved exposed deep structures such as bone or tendon. Of 57 wounds with photographs, 34 (60%) had wound beds of predominantly devitalized tissue (eschar or slough). Based on patient report, 28 wounds (48%) were acute (<1 month old), 12 (20%) were subacute (present for 1-3 months), and 17 (29%) were chronic (developed ≥3 months prior). Subacute and chronic wounds were more often medium or large in size (odds ratio, 48.5; 95% CI, 8.2-1274.8; P < .001) and more frequently had devitalized wound beds (odds ratio, 9.5; 95% CI, 2.9-37.0; P < .001).

Conclusions and relevance: In this case series of hospitalized patients with confirmed xylazine exposure, wounds were commonly located on extensor surfaces of the extremities, frequently had devitalized tissue or exposed deep structures, and were more likely to have larger and necrotic wound beds the longer they had persisted. This systematic characterization of xylazine-associated wounds may inform identification, management, and research to address this emerging public health threat.