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.
Bahrami
Soon
S
Department of Pathology, University of Louisville School of Medicine, Louisville, KY 40292, USA.
Malone
Janine C
JC
Webb
Kelli G
KG
Callen
Jeffrey P
JP
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