Erythema Multiforme Reaction to Sestamibi

TO THE EDITOR:

Allergic reactions to radioisotopes are uncommon, but all nuclear physicians need to be aware of possible reactions to radioisotopes in everyday practice. We would like to draw your attention to a previously unreported reaction to ^99mTc-sestamibi experienced by a woman having parathyroid imaging.

^99mTc-sestamibi was prepared and administered according to the manufacturer’s guidelines. There was no past history of allergy or dermatologic disorder. Over 48 h, the patient developed an erythematous papulovesicular rash on the trunk, arms, and scalp with target lesions typical of erythema multiforme. A skin biopsy confirmed histologic features consistent with erythema multiforme.