title: Cross-comparison of patch test and lymphocyte proliferation responses in patients with a history of acute generalized exanthematous pustulosis.
abstract: An adverse cutaneous reaction to a systemically administered drug may rarely manifest as acute generalized exanthematous pustulosis (AGEP). Several recent reports have documented positive patch test results in patients with a history of AGEP, while two have demonstrated drug-specific in vitro lymphocyte proliferative responses. These findings suggest that drug-specific T cells mediate AGEP. We describe two patients with a history of AGEP who each demonstrated positive patch test results specific for the inciting drug: Patient #1 to the antibiotic metronidazole, and Patient #2 to the calcium channel-blocker diltiazem. Histologic examination of biopsy specimens taken from the patch test sites of these patients revealed spongiotic dermatitis and perivascular lymphocytes consistent with a delayed-type hypersensitivity reaction, rather than demonstrating subcorneal neutrophilic pustules more typical of AGEP. In vitro testing by measuring peripheral T cell proliferative responses to chemically purified drug correlated with the clinical response. In a direct cross-comparison, patch test results were shown to correlate with in vitro lymphocyte proliferative responses in two patients with a history of AGEP to different drugs. These findings provide additional evidence that the pathogenesis of AGEP involves a T cell-mediated immune response.
authors.affiliation: Departments of Dermatology, Yale University School of Medicine, New Haven, CT 06520, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Girardi
authors.forename: Karynne O
authors.initials: KO
authors.lastname: Duncan
authors.forename: Robert E
authors.initials: RE
authors.lastname: Tigelaar
authors.forename: Suguru
authors.initials: S
authors.lastname: Imaeda
authors.forename: Kalman L
authors.initials: KL
authors.lastname: Watsky
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: McNiff
mesh_terms: D000328:Adult; D000368:Aged; D000890:Anti-Infective Agents / Q000009:adverse effects; D002121:Calcium Channel Blockers / Q000009:adverse effects; D049109:Cell Proliferation; D004110:Diltiazem / Q000009:adverse effects; D003875:Drug Eruptions / Q000276:immunology* / Q000473:pathology; D004342:Drug Hypersensitivity / Q000276:immunology*; D005260:Female; D006801:Humans; D007158:Immunologic Techniques; D008297:Male; D008795:Metronidazole / Q000009:adverse effects; D010328:Patch Tests; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000890:Anti-Infective Agents; D002121:Calcium Channel Blockers; D008795:Metronidazole; D004110:Diltiazem