Iododerma Following Radioactive Iodine Therapy in Thyroid Cancer: Insights From 2 Cases.

Radioactive iodine ablation is commonly used to treat thyroid diseases. However, despite its efficacy, it has inherent risks and complications. One such complication is iododerma. This rare dermatological condition triggered by iodine exposure has been infrequently documented in association with radioactive iodine therapy for thyroid diseases. Here, we present 2 cases of iododerma following radioactive iodine ablation for thyroid cancer. In the first case, a 38-year-old female developed facial swelling and red blotchy rashes accompanied by papules on the left upper eyelid. Despite initial worsening of symptoms, the patient improved after prednisone treatment. In the second case, a 71-year-old male with metastatic follicular thyroid cancer received iodine-131 therapy after levothyroxine withdrawal for pulmonary metastasis. Approximately 1 week posttherapy, he developed a nontender, nonpruritic rash on the extremities and anterior abdomen, which spontaneously resolved without intervention. Iododerma presents diagnostic challenges because of its rarity and diverse cutaneous manifestations. Although its exact pathophysiology remains unclear, it has been hypothesized to be induced by hypersensitivity reactions to and delayed clearance of iodine from the body. Physicians should be aware of this rare complication of radioactive iodine in patients with thyroid disease.