Tissue eosinophilia as an indicator of drug-induced cutaneous small-vessel vasculitis.
OBJECTIVE
To determine whether tissue eosinophilia is a reliable indicator of a drug-induced etiology in biopsy samples demonstrating leukocytoclastic vasculitis.


METHODS
Retrospective medical record review with concurrent histopathologic analysis.


METHODS
University-affiliated dermatology practice.


METHODS
Sixty-three patients with cutaneous small-vessel vasculitis meeting specific inclusion criteria were divided into drug-induced (n = 16) and non-drug-induced (n = 47) groups.


METHODS
Corresponding histopathologic material was reviewed by a dermatopathologist masked to the etiologic associations. An eosinophil ratio was calculated for each patient, derived from the mean eosinophil score (averaging eosinophil counts from 10 high-power histologic fields), and expressed in relation to the intensity of inflammation in the histopathologic slides examined. Eosinophilia ratios were compared for both groups using the Mann-Whitney test.


RESULTS
A significant difference was found in mean eosinophil ratios in the drug-induced vs non-drug-induced groups (5.20 vs 1.05; P = .01). Vascular fibrin deposition was present in both groups and was not found to be significantly different (P = .78). Clinical evidence of systemic vasculitis was present in 2 patients (13%) in the drug-induced group vs 15 (32%) in the non-drug-induced group. Fourteen patients (88%) in the drug-induced group had a short-term disease course vs 27 (57%) in the non-drug-induced group.


CONCLUSIONS
Tissue eosinophilia is established as a reliable indicator of drug induction in cutaneous small vessel vasculitis. Drug-induced small-vessel vasculitis generally follows a short-term disease course without development of systemic involvement. This information may be useful for guiding management decisions, especially when the etiology is unclear.
Department of Pathology, University of Louisville School of Medicine, Louisville, KY 40292, USA.
Soon
S
Bahrami
Janine C
JC
Malone
Kelli G
KG
Webb
Jeffrey P
JP
Callen
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000009:adverse effects*; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D004802:Eosinophilia / Q000209:etiology / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012867:Skin / Q000473:pathology*; D018366:Vasculitis, Leukocytoclastic, Cutaneous / Q000139:chemically induced* / Q000150:complications / Q000473:pathology
D000900:Anti-Bacterial Agents