Radiopharmacy: Delayed Skin Rash Following Administration of Technetium-99m Diphosphonate: A Case Report

Abstract

We report a case of a 48-yr-old woman who developed a delayed skin rash following intravenous (i.v.) administration of technetium-99m hydroxymethylene diphosphonate (^99mTc-HDP). The rash was characterized by skin biopsy, and it was concluded that the reaction was due to the diphosphonate compound. The rash resolved spontaneously without treatment. With most ^99mTc-based agents, adverse reactions are considered rare and are usually allergic in nature, but the delayed nature of this reaction is more common with diphosphonate compounds than with other radiopharmaceuticals. If a repeat examination is required, alternative agents (such as ^99mTc-pyrophosphate) or any other diagnostic modality (magnetic resonance imaging) may be considered. An intradermal skin test may be helpful to determine the safest alternative bone agent.