Delayed Hypersensitivity Reaction to Iodinated-Contrast Following Lumbar Epidural Steroid Injection: Case Report

Delayed hypersensitivity reactions to an iodinated radiologic contrast are a form of hypersensitivity reactions that occurs anywhere from one hour up to 10 days after exposure to the causative agent.

We present a case of a 54-year-old woman with a history of a single minor reaction to an intravenous iodinated contrast consisting of only abdominal pain who developed a maculopapular exanthema 7 days after exposure to iohexol, an iodinated radiological contrast, during a lumbar epidural steroid injection. The patient was later treated with topical betamethasone with resolution of cutaneous symptoms within 2 weeks. The patient then underwent patch testing, which revealed a positive result for palladium (II) chloride; to date, there has been no documented association in the literature between palladium (II) chloride and iohexol.

DHRs to an iodinated radiologic contrast can range from cutaneous manifestations to lethal presentations, such as Stevens-Johnson syndrome and toxic epidermal necrolysis, with the most common form being a maculopapular exanthema as experienced by our patient. Testing can be performed to determine the causative agent of the DHR and to find an alternative agent if a radiologic contrast is required. Caution must be taken if using an alternative contrast agent as there is significant cross-reactivity to other iodinated radiologic contrasts.