Iodism

Iodism is the term for a syndrome of symptoms resulting from excessive exposure to iodine or iodide. It is also described as iodide poisoning and can follow high-dose ingestion of iodide preparations such as potassium iodide or Lugol’s solution, inhalation of iodine vapors, or prolonged exposure to iodinated contrast agents. Chronic exposure to iodide-containing medications or contaminated water may yield a milder, ongoing form of iodism.

Clinically, iodism presents with a combination of mucosal irritation and systemic signs. Early features often include a metallic taste, sore throat or coryza, mouth ulcers, excessive salivation, and conjunctivitis. A skin eruption resembling dermatitis or acneiform changes may occur with longer exposure. Gastrointestinal symptoms such as nausea, anorexia, and diarrhea can accompany the illness. In susceptible individuals, excess iodine can perturb thyroid function, causing transient hypothyroidism via the Wolff-Chaikoff effect or, conversely, precipitating iodine-induced hyperthyroidism (Jod-Basedow) in those with preexisting thyroid disease or iodine deficiency.

Diagnosis is based on a history of recent iodine exposure and compatible clinical findings, supported by laboratory data such as elevated urinary iodine excretion and assessment of thyroid function to identify disturbances. Management centers on stopping iodide exposure and providing supportive care. Severe cases may require medical supervision and, if needed, treatment of any resultant thyroid dysfunction. Most patients recover after iodine levels fall, though dermatitis and mucosal symptoms may take time to resolve.

Prevention focuses on careful use and dosing of iodide-containing medications, awareness of cumulative iodine intake, and monitoring in individuals with thyroid disease or in populations at risk for iodine imbalance.