Can you outgrow your codeine allergy?

Unlikely: Codeine allergy can be true allergy (caused by immunoglobulin e that reacts with the Codeine molecule) or because Codeine can directly cause allergic mediator release from mast cells and basophils by a non-immunoglobulin e mechanism. One can use Codeine as a positive control rather than histamine for skin testing. One can be desensitized to a number of drugs but Codeine is not commonly attempted.

Probably not: Reactions to Codeine usually occur because it is a narcotic which can cause nausea and vomiting and directly activate cells in the body which contain histamine, called mast cells. In sensitive individuals Codeine causes mast cells to release histamine causing flushing, itching, hives, swelling of skin/lips, etc. The sensitivity persists but can pretreat or use fentanyl (less mast cell activation).