text: Some people develop a hypersensitivity to compounds of iodine but there are no known cases of people being directly allergic to elemental iodine itself. Notable sensitivity reactions that have been observed in humans include:
  * The application of tincture of iodine may cause a rash.
  * Some cases of reaction to povidone-iodine (Betadine) have been documented to be a chemical burn.
  Medical use of iodine compounds (i.e. as a contrast agent) can cause anaphylactic shock in highly sensitive patients, presumably due to sensitivity to the chemical carrier. Cases of sensitivity to iodine compounds should not be formally classified as iodine allergies, as this perpetuates the erroneous belief that it is the iodine to which patients react, rather than to the specific allergen. Sensitivity to iodine-containing compounds is rare but has a considerable effect given the extremely widespread use of iodine-based contrast media; however, the only adverse effect of contrast material that can convincingly be ascribed to free iodide is iodide mumps and other manifestations of iodism.