Dye rashes.

Physicians may administer intravenous dyes to patients, most commonly to delineate vascular or urinary anatomy, without an appreciation of the potential hazards associated with these compounds. We report two cases in which skin eruptions followed the intravenous administration of the dyes fluorescein and methylene blue; these eruptions were the same colors as the dyes. In our first patient, urticaria, which was yellowish in color and fluorescent under a Wood's lamp, occurred after the administration of fluorescein. In the second patient, painful blue macules appeared randomly on the forearm within 15 seconds after methylene blue was injected into a free-flowing intravenous cannula on the dorsal aspect of the hand.