Diltiazem-Induced Drug Eruption Sparing Seborrheic Keratoses

A case of a diltiazem-induced morbilliform drug eruption, which spared the circumferential margin of seborrheic keratoses, is presented. Hypotheses regarding the pathogenesis of this novel exanthem are discussed. The potential mechanisms may be immunologic involving cytokines, or due to diminished levels of prostaglandin E2, altered optical properties of the skin, mechanical pressure phenomena, or altered local vasoconstriction secondary to diltiazem itself.