That may be true, I was just pointing out too much of anything can interfere with normal biological functioning. It wouldn't be considered an allergy, but it's still detrimental nonetheless. You can overdose on water for example.
Discussion
Iodine from the contract can absolutely cause acute thyrotoxicosis called "thyroid storm" in some rare cases, which is why it is (theoretically) important to check TSH/fT4 levels before doing an iodine contrast CT scan.
But it's not an allergy, and is not a contraindication to perform a contrast CT.