Ziebart, Rachel L

ABSTRACTBackgroundDrug‐induced hypersensitivity syndrome (DiHS), or drug reaction with eosinophilia and systemic symptoms (DRESS), is a delayed and severe immune response to certain medications. We investigated vancomycin‐induced DiHS/DRESS, notable for frequent and severe organ involvement, to describe its specific histopathology and the correlations between histopathologic and clinical findings.MethodsA retrospective review was conducted to identify patients between 2006 and 2022 who received vancomycin, had archived skin biopsy specimens, and were scored as having probable or definite DiHS/DRESS. Clinical features were retrospectively collected, and biopsy specimens were reviewed by a board‐certified dermatopathologist. A subset of histopathologic and clinical features was analyzed for statistical correlation.ResultsTwenty‐three patients met the inclusion criteria. Most biopsy specimens (87%) showed an eczematous reaction pattern; 17 (74%) showed a secondary reaction pattern. Spongiosis (87%) and neutrophilic infiltration (91%) were common epidermal characteristics. The dermal inflammatory infiltrate was frequently superficial (87%) and consistently included plasma cells (96%). Eosinophils were present in the dermis in 70% of cases. Parakeratosis negatively correlated with liver involvement and positively correlated with desquamative rash. Epidermal lymphocytes were negatively correlated with the RegiSCAR score.ConclusionsVancomycin‐associated DiHS/DRESS histopathology was characterized by a frequent eczematous reaction pattern, multiple coexisting reaction patterns, and epidermal neutrophilic infiltration.